PDF Summary:Good Calories, Bad Calories, by Gary Taubes

In Good Calories, Bad Calories, Gary Taubes challenges the widely-held belief that dietary fat is the primary cause of heart disease and other chronic illnesses. He presents an alternative theory: that the real culprit is refined carbohydrates and sugars.

Taubes scrutinizes the evidence behind the diet-heart hypothesis, including nutritional studies, animal research, and clinical trials. He argues the data does not conclusively link dietary fat to disease, and he traces how bias and flawed research methods may have contributed to the hypothesis persisting. Taubes then explores the carbohydrate hypothesis, which implicates a hormone called insulin—stimulated by carb consumption—in obesity, heart disease, and other modern health issues.

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The case of the Pima Indians in Arizona is viewed by Gary Taubes as conclusive evidence that the consumption of carbohydrates affects the prevalence of chronic illnesses. The Pima, who prospered in the past through farming and supplemented their diet with foraging and hunting, are currently recognized for having the most widespread occurrence of diabetes in the nation, and possibly in the world. During the late 1800s, the Pima people, having been forced onto reservations, experienced a substantial reduction in their traditional food sources, resulting in an extended duration of severe hunger. In the early 1900s, the Pima's diet consisted mainly of rations provided by governmental agencies. In 1901, Frank Russell, an anthropologist from Harvard, noted that obesity was notably prevalent in the community, which was a marked deviation from the commonly revered physique of Native Americans, often described as tall and lean. In the 1950s, the prevalence of diabetes among the Pima community surpassed that of the wider U.S. populace, a situation that aligned with the shift in their traditional eating patterns following the government's distribution of processed sugars and cereals, along with increased availability of sodas, sweets, crisps, and baked goods at local stores on their reservations. By the 1970s, diabetes had become prevalent in half of the Pima population, who were also becoming well-known for their escalating struggles with excessive weight, cardiovascular diseases, and other persistent health issues. Gary Taubes argues that the health issues they faced are typical of conditions arising from modern eating habits that emphasize a high intake of carbohydrates and a low intake of fats, particularly as a result of indulging in sugary treats, refined grains, white rice, and soda.

Practical Tips

• Create a 'modern activity swap' list where for each typically sedentary modern activity you do, you find an active, traditional counterpart. For instance, instead of using a car for short distances, choose to walk or cycle, emulating the more physically demanding lifestyle of past generations. Or, swap an hour of television with gardening, crafting, or playing a musical instrument, which involves more diverse movements and can be more socially engaging.
• Experiment with one new low-carbohydrate recipe each week to diversify your diet. By focusing on variety, you'll be less likely to feel restricted and more likely to discover enjoyable, healthier meal options that could become staples in your routine.
• Engage with local food initiatives by volunteering or participating in community-supported agriculture (CSA). This will give you a firsthand look at the challenges and rewards of sourcing food locally and sustainably. Through this, you can better appreciate the complexities that communities like the Pima face when their traditional food sources are disrupted.
• Create a personal challenge to swap out processed foods with whole food alternatives for one month. During this time, take note of any changes in your energy levels, weight, and overall well-being. This self-experiment can offer insights into the effects of a diet closer to traditional eating patterns, much like the Pima community's original diet.
• Experiment with traditional cooking methods from cultures known for low cardiovascular disease rates. Research and try out recipes from the Mediterranean or Okinawan diets, which emphasize whole foods, healthy fats, and lower carbohydrate intake. By incorporating these cooking styles into your weekly meal planning, you can diversify your diet and potentially improve your health markers.

The hypothesis has developed to highlight the significance of dietary fiber instead of merely concentrating on processed carbs.

Taubes argues that during the 1970s, the idea that processed carbohydrates might be detrimental was eclipsed by the increasing acceptance of the diet-heart hypothesis, which subsequently influenced dietary guidelines.

The hypothesis linking what we eat to the health of our heart and blood vessels gave rise to the assumption that eating less fat would naturally lead to a higher intake of carbohydrates. Proponents of the diet-heart hypothesis associated obesity with overeating and believed that fat, because of its dense caloric value, was particularly prone to contribute to weight gain. They thus advocated for a dietary approach that emphasizes the reduction of total calories and fats, which consequently leads to a diet predominantly composed of carbohydrates.

Taubes suggests that the hypothesis linking contemporary chronic ailments to sugar and refined carbohydrates has been adapted into a more widely acceptable form, asserting that the health issues stem not from the carbohydrates per se, but from the removal of fiber in the process of refining them. Taubes thoroughly documents the rise and eventual fall of this theory, illustrating how compelling and apparently trustworthy perspectives can frequently overshadow actual scientific evidence, thus impeding progress in the field.

Attention turned to the absence of dietary fiber rather than the presence of refined carbohydrates.

Taubes recounts how, in the late 1960s, Denis Burkitt, a former missionary surgeon, began advocating the notion that a lack of dietary fiber due to the consumption of refined carbohydrates was a primary cause of many diseases. Burkitt, who gained recognition in the healthcare field in the 1960s following his discovery of a cancer that bears his name, Burkitt's lymphoma, and its likely viral origin, developed his theory based on the insights of British naval physician Peter Cleave, who introduced the concept of "saccharine disease" to describe the potential consequences of consuming refined carbohydrates such as sweeteners, processed wheat, and polished rice, which include the development of obesity and diabetes.

Taubes observes that while Burkitt was considerably impacted by Cleave's studies, he believed it was overly reductive, in terms of both politics and science, to solely blame white flour and sugar, which had become staples in Western diets. Additionally, he worked closely with Harold Himsworth, who later became the head of Britain's Medical Research Council, and was a firm opponent of the idea that sugar contributed to the development of diabetes in the 1930s and 40s. Burkitt supported Cleave's hypothesis, highlighting that the removal of fiber in the refining process was the issue, rather than the refined carbohydrates themselves.

In the early 1970s, Burkitt collaborated with Hugh Trowell, a missionary doctor who had significant experience in Kenya, to write a medical textbook that emphasized the advantages of consuming dietary fiber and discussed the illnesses often associated with Western lifestyles. Trowell coined the term "Western diseases" to avoid implying to medical students from Africa and Asia that the rarity of such conditions in their homelands was a sign of being uncivilized.

Burkitt and Trowell acknowledged the importance of incorporating the idea that consuming saturated fat elevates the likelihood of developing heart disease into the diet-heart hypothesis. Trowell's summary suggested that a diet with a focus on carbohydrates and less fat might guard against heart disease, yet it also observed a decrease in the consumption of fibrous, starchy foods. Taubes contends that their final judgments are largely dependent on personal beliefs and subjective analysis. The dominant view held that diets rich in fat and those containing a significant amount of saturated fat might contribute to the development of heart disease; this danger, however, could be lessened by including a generous portion of carbohydrates that are abundant in fiber. It was proposed that carbohydrates deficient in fiber might provide only limited defense against illness.

Taubes contends that the widespread endorsement of the fiber hypothesis owed more to Burkitt and Trowell's charismatic persuasiveness and their knack for garnering media spotlight than to solid scientific proof, which was, at most, ambiguous and limited.

Practical Tips

• Experiment with new recipes that use natural sweeteners like honey, maple syrup, or dates instead of refined sugars. This can be a fun way to explore different flavors and learn which natural sweeteners you prefer. Try making a batch of oatmeal cookies sweetened with mashed bananas or a homemade granola using a touch of honey.
• Experiment with a "fiber swap challenge" for a week, where you replace processed snacks with whole food alternatives. Instead of reaching for chips or cookies, try snacking on nuts, fruits, or vegetables with hummus. Keep a journal to note any changes in how you feel, such as increased satiety or improved digestion, which can motivate you to make long-term changes.
• You can track your fiber intake by using a food diary app to ensure you're meeting recommended dietary guidelines. Start by downloading a nutrition tracker app that allows you to log your meals and snacks. Look for one with a database that includes a wide variety of whole foods and provides detailed nutritional information, including fiber content. Aim to meet the fiber intake recommendations for your age and sex, which you can find on health authority websites.
• Encourage empathy and understanding by engaging in role-reversal exercises during discussions with friends or family. When a topic involving cultural differences arises, consciously adopt the perspective of someone from a different cultural background. This practice can help you understand the impact of language and labels on individuals from diverse cultures. For instance, if discussing health issues prevalent in certain regions, consider how those living there might feel about the terms used to describe their health challenges.
• Create a swap chart for your kitchen that lists high-fat ingredients alongside healthier carbohydrate-rich alternatives. Use this chart when cooking to make real-time substitutions that align with the dietary approach you're exploring. An example would be using applesauce or mashed bananas in place of oils when baking, or opting for quinoa instead of white rice to increase your fiber intake.
• Experiment with substituting high-fiber alternatives in traditional recipes. For example, if you enjoy baking, try replacing some of the white flour with whole grain flour or adding oats and nuts to increase the fiber content. When cooking savory dishes, incorporate legumes like lentils or chickpeas, which are not only high in fiber but also have a lower saturated fat content compared to animal proteins.
• Create a discussion group with friends or family where you can share and scrutinize health-related information. Each member could bring a piece of health advice they've heard recently, and together you can investigate its origins and scientific backing. This collective approach not only helps in discerning fact from hype but also promotes a supportive environment for making health-related decisions.

Despite facing scrutiny, the belief that fiber prevents chronic disease continues to be held by some, even when confronted with evidence that suggests otherwise.

Taubes investigates how the concept that insufficient dietary fiber causes sickness became widely accepted, particularly after a 1974 article in the Journal of the American Medical Association examined Burkitt and Trowell's studies, drawing attention from the press and leading the Washington Post to acclaim it as a modern solution. The emphasis on consuming wholesome, unprocessed foods rapidly swayed breakfast cereal manufacturers to promote the cardiovascular benefits of bran in their offerings.

He subsequently showed that, despite the substantial investment in research, it did not provide consistent backing for the proposed theory. In research suggesting beneficial effects of fiber, typically involving a small group of participants, these individuals usually increased their consumption of plant-based foods such as fruits, vegetables, and whole grains while also decreasing the amount of fats they ate. Research involving 49,000 women from the Women's Health Initiative in 2006 revealed that increasing dietary fiber intake did not result in reduced occurrences of heart disease or colorectal cancer.

Taubes explores how prominent individuals in the health sector, along with journalists, continued to endorse a specific dietary approach despite the lack of corroborative evidence, relying solely on its hypothetical advantages. Taubes observes that the hypothesis initially put forward by Burkitt gained worldwide acceptance, its credibility has gradually diminished over time. Taubes emphasizes the significant difficulty in definitively ascertaining the effects of these nutritional regimens on health through clinical studies, particularly as deeper scrutiny indicates that such assurance may be hard to come by.

Other Perspectives

• Dietary fiber's role in preventing sickness may be overstated, but it is still an essential component of a balanced diet for maintaining digestive health.
• The enthusiasm generated by the media coverage could have contributed to a confirmation bias, where subsequent studies were designed or interpreted in a way that favored the fiber hypothesis.
• The promotion of bran's cardiovascular benefits by cereal manufacturers could be seen as an oversimplification of health benefits that may not be supported by strong scientific evidence.
• The Women's Health Initiative study mentioned might not be representative of the general population, as it focused on a specific group of women, which could limit the generalizability of its findings.
• The beneficial effects observed might be due to nutrients or phytochemicals in plant-based foods other than fiber.
• Subsequent studies might have found different results, suggesting that the findings from the 2006 study are not conclusive.
• Prominent health sector individuals and journalists may endorse certain dietary approaches based on the precautionary principle, advocating for dietary fiber due to its potential benefits and the low risk of harm associated with its consumption.
• The loss of credibility over time could be indicative of the rigorous nature of scientific inquiry, where hypotheses are constantly tested and re-evaluated in light of new data and methodologies, rather than a failure of the original hypothesis.
• Advances in research methodologies and statistical analysis have improved our ability to control for confounding variables, making it more feasible to isolate the effects of specific dietary components.
• The lack of assurance in some studies may be due to variations in the types of fiber consumed, the overall diet and lifestyle of participants, or other environmental factors, rather than an indication that fiber does not affect health.

The foundational principles underlying the Carbohydrate Hypothesis.

Taubes reexamines the concept of the saccharine disease, delving into the metabolic and hormonal processes associated with blood lipids, insulin, and the control of fat metabolism that might have been spotlighted if the scientific community had properly acknowledged their significance, providing an alternative viewpoint that diverges from the exclusive focus on the roles of dietary fat and cholesterol, as well as the significance of fiber. Taubes proposes that understanding these mechanisms can elucidate the causes of our weight gain, the particular locations of fat deposition, the intense cravings for rapidly digestible carbs often felt by those who are overweight, and the rationale for why focusing on the exclusion of these carbs from one's diet, rather than just reducing total caloric intake or increasing physical activity, is the most effective method for losing weight and fat. He also argues that the factors contributing to significant weight gain are probably the same as those responsible for chronic diseases in modern society.

The process of managing the breakdown and use of fats

Taubes explores the complex mechanisms that control how fat is allocated and managed within the body, examining the hormonal and molecular frameworks that determine how much fat is utilized for energy, how much is conserved, and where it is specifically stored. Taubes highlights the critical function of insulin, a hormone secreted by the pancreas, in maintaining blood sugar balance. Gary Taubes has pinpointed insulin as the key regulator of fat metabolism. Elevated insulin levels in the blood may result in a greater buildup of fat and may hinder the body's ability to tap into these fat stores when needed. People who suffer from obesity or diabetes frequently have elevated insulin levels in their blood, a state referred to as hyperinsulinemia, and their body tissues tend to become less responsive to the actions of insulin.

Adipose tissue primarily relies on the metabolism of fat for its energy needs, constantly exchanging fatty acids within its cellular structure.

Taubes challenges the widespread misunderstanding that fat is simply a reserve of excess energy, utilized by the body solely during periods of scarcity. The concept emerged from early research on diabetes, which mistakenly indicated that glucose served as the primary fuel for the body, while fat was metabolized for energy only in rare situations, like prolonged fasting or the dangerous ketoacidosis that diabetics faced before insulin therapy became common.

However, Taubes points out that studies on fat metabolism initiated in the 1920s by Rudolf Schoenheimer at Columbia University revealed that fat doesn't just accumulate in fat tissue to be used when the body requires the energy, but instead is in a constant state of flux, circulating through the liver, heart, skeletal muscles, and other parts of the body. Schoenheimer showed that fats, whether ingested or synthesized from carbohydrates by the liver and fat cells through de novo lipogenesis, are metabolized into fundamental fatty acids and subsequently reassembled within the fat cells into a type of fat known as triglycerides, rendering their origin indiscernible. Taubes describes an ongoing cycle in the blood where fat and fatty acids are used for energy, transformed into triglycerides by the liver, or sent back to the body's fat cells to be stored.

The idea that fat is stored in adipose tissue simply as a result of consuming excess calories has been effectively contested by Ernst Wertheimer, an Israeli biochemist. Consequently, Taubes argues that the regulation of fat storage or depletion in adipose tissue is not dictated by the quantity of calories consumed; rather, he proposes that the effect occurs at the cellular level, with insulin being the key factor.

Practical Tips

• Engage in regular, moderate-intensity exercise, like brisk walking or cycling, to increase the demand for energy from fat stores. Aim for at least 150 minutes per week, as recommended by health guidelines, and use a fitness tracker to monitor your activity levels and ensure consistency. This practice not only supports fat metabolism but also contributes to overall health and well-being.
• Engage in a simple at-home science experiment to visually understand the density of fat compared to muscle by using common household items. Fill one balloon with water to represent muscle and another with an equal volume of vegetable oil to represent fat. Weigh both balloons to feel the difference in weight, and then try to float them in a tub of water to see how they behave differently, mimicking how muscle and fat differ in density and buoyancy in the body.
• Engage in a self-guided learning project about the biochemical pathways of fat metabolism. Use free online resources such as educational videos, articles, and interactive tools to deepen your understanding of how fats are broken down and used for energy in the body. Apply this knowledge to make informed choices about your diet and exercise habits, aiming to support your body's natural fat flux processes.
• Track your sleep and stress levels alongside your diet for a month to see if there's a correlation with weight changes. Use a simple spreadsheet or journal to record your sleep duration, sleep quality, stress levels, daily food intake, and body weight. This can help you identify patterns that may suggest factors other than calorie intake are influencing your weight.

The process by which dietary carbohydrates and insulin contribute to fat storage in adipose tissue.

Taubes elucidates that the quantity of fat our bodies utilize as energy, commonly referred to as fat oxidation, is contingent upon the glucose levels processed by our cells, which in turn is influenced by our carbohydrate intake and the efficiency of the insulin produced to regulate blood sugar levels.

During the process of energy production, the molecule known as glycerol phosphate is synthesized solely within the liver and adipose cells as blood glucose undergoes metabolism. Glycerol phosphate serves not only as a source of energy but is also essential in the process of combining three fatty acid molecules to form a triglyceride, which is a type of fat molecule. When a fat cell possesses sufficient glycerol phosphate, it is capable of efficiently trapping fatty acids, whether they are in the bloodstream or released from other fat cells, and transforming them into stored triglycerides via esterification. Fat cells cannot retain fatty acids in the absence of adequate glycerol phosphate. Once reabsorbed, these substances provide support for the activities of various tissues and organs.

The concentration of glycerol phosphate in the body is influenced by the levels of glucose in the blood and the quantity of glucose that is delivered to fat tissue. After consuming meals high in carbohydrates, blood sugar levels increase, facilitating the uptake of glucose by fat cells and boosting the synthesis of glycerol phosphate due to the more vigorous use of glucose for energy. As a result, fat cells engage in a transformation where they convert fatty acids and retain them in the form of fat deposits. During periods when our bodies lack glucose, like after consuming food with minimal carbs or while we are asleep, the process that permits glucose to infiltrate and break down within fat cells is markedly reduced. When fat cells fail to produce enough glycerol phosphate, it leads to an increased discharge of fatty acids into the bloodstream. During the night, these substances can serve to power our muscle movements, internal bodily operations, and cognitive activities.

In a 1963 article published in JAMA, Edgar Gordon, an endocrinologist at the University of Wisconsin, observed that for obesity to develop and remain, the body must transform glucose into fat.

Gordon also emphasized the crucial role of insulin in the development of obesity, given its status as the main hormone that channels glucose into fat cells and various other tissues.

Practical Tips

• Engage in a mindfulness practice focused on bodily sensations during and after meals or physical activity to become more attuned to your body's energy production and storage signals. Mindfulness can help you become more aware of subtle changes in your body that may be associated with the synthesis of glycerol phosphate and other metabolic processes. For instance, after eating a meal rich in fats, you might meditate and pay attention to any feelings of satiety, warmth, or sluggishness, which could provide clues about your body's metabolic responses.
• You can enhance your dietary intake with foods rich in choline, such as eggs and liver, to potentially support the production of glycerol phosphate. Choline is a nutrient that plays a role in the synthesis of phospholipids, which are essential for the production of glycerol phosphate. By incorporating choline-rich foods into your meals, you may indirectly support the trapping and storage of fatty acids as triglycerides in fat cells.
• Engage in a 30-day exercise challenge to observe the effects on your glucose metabolism. Commit to a daily physical activity, whether it's a brisk walk, a bike ride, or a dance class, and note any changes in how you feel physically and mentally. Exercise is known to influence glucose levels, and this challenge can help you find the right balance and frequency of activity for your body.
• Incorporate a moderate exercise routine during times you suspect your body is utilizing fatty acids, like a brisk walk or light jog before breakfast. Track how you feel during these workouts compared to after meals to gauge if there's a noticeable difference in your endurance or muscle performance.
• Experiment with timing your carbohydrate intake around periods of higher physical activity. Since your muscles use glucose for energy during exercise, consuming carbs before or after your workout could potentially reduce the amount of glucose available for conversion into fat. Try having a serving of carbs, like a banana or a small bowl of oatmeal, before your next gym session and observe how you feel and perform.
• Experiment with intermittent fasting by setting a daily eating window, such as 8 hours of eating followed by 16 hours of fasting. This approach can help regulate the amount of insulin your body releases, as less frequent eating can lead to lower insulin spikes. Start with a manageable fasting window and gradually increase it as your body adapts.

Blood sugar levels and energy management are governed by two main metabolic pathways: one involves the cycle of triglycerides, while the other is associated with the interplay between glucose and fatty acids.

Taubes delves into the complexities surrounding the body's fat storage and energy mobilization mechanisms, detailing the transformation of triglycerides and the interaction of glucose with fatty acids in a metabolic pathway identified by British biochemist Sir Philip Randle in the early 1960s, now known as the Randle cycle.

The liver's cells absorb unbound "free" fatty acids and convert them into a form of fat called triglycerides, which are subsequently included into lipoproteins. Lipoprotein lipase, often abbreviated as LPL, plays a role in disassembling triglycerides, which results in the release of fatty acids into the bloodstream, where they are absorbed by different tissues. The cycle of triglycerides and fatty acids sustains the ongoing transfer of fats among the liver, adipose tissue, and other organs that use them for energy. The process of triglyceride formation in fat cells is greatly affected by the availability of glucose and glycerol phosphate, which control this biological mechanism.

Muscle cells switch between using glucose and fats for energy, a process referred to as the glucose/fatty acid cycle. The more glucose that is burned for energy, the less fat will be oxidized. The body's energy reliance shifts towards fat, resulting in a corresponding decrease in glucose utilization. This ensures a consistent flow of energy to the muscles and helps maintain stable blood sugar levels. When blood sugar levels are low, the release of fatty acids from fat stores hinders muscle cells from using glucose in the bloodstream. The brain and nervous system, therefore, can utilize an increased quantity of glucose as a source of energy. An excess of blood glucose increases glucose oxidation in muscles, consequently inhibiting fatty acid metabolism and causing these acids to be either stored in fat cells or converted into triglycerides by the liver.

The triglyceride/fatty acid cycles and the Randle cycle play a crucial role in stabilizing blood glucose levels and in the effective distribution of energy throughout the body's cells. Any malfunction within these systems can lead to various chronic illnesses, including obesity and diabetes.

Practical Tips

• Incorporate a weekly meal-prep day to create balanced meals that support a healthy transfer of lipids in the body. By preparing meals that include a variety of nutrients, with a focus on healthy fats, fiber-rich carbohydrates, and lean proteins, you can influence the way your body processes and distributes triglycerides and fatty acids. An example meal could be grilled salmon with quinoa and steamed broccoli, which provides omega-3 fatty acids, complex carbs, and protein.
• Monitor your macronutrient intake using a food tracking app to observe how your body's energy sources shift throughout the day. By logging your meals, you can see the balance between carbohydrates (glucose) and fats in your diet and correlate this with your energy levels or workout performance. For example, if you eat a high-fat, low-carb breakfast, you might notice sustained energy without a sugar crash, suggesting a fat-based energy usage.
• Engage in dual-mode training, alternating between high-intensity interval training (HIIT) and low-intensity steady-state (LISS) cardio across different sessions. HIIT may favor glucose utilization due to its high intensity, while LISS might tap more into fat reserves. By varying your workouts, you can explore how your body adapts to using different energy sources and potentially improve your metabolic flexibility.
• Incorporate a weekly cooking ritual where you prepare homemade, high-fat, low-carb snacks. This could include making a batch of keto-friendly energy balls or avocado-based chocolate pudding. Having these on hand can help you resist the temptation of high-sugar snacks and maintain more stable blood sugar levels throughout the day.
• Use a continuous glucose monitor (CGM) to get real-time feedback on how different foods and activities affect your blood glucose levels. While traditionally used by individuals with diabetes, CGMs are becoming more popular for those interested in understanding their metabolic health. Observing how your glucose levels fluctuate in response to meals, stress, and sleep can empower you to make lifestyle adjustments that support better fatty acid metabolism, like choosing snacks that combine proteins and fats instead of reaching for a sugary granola bar.

Insulin plays a role in promoting the build-up of fats and the onset of obesity.

Taubes argues that understanding the rules that control fat metabolism is essential for acknowledging how carbohydrates contribute to weight gain and realizing that removing them from one's diet may result in weight loss, independent of the number of calories consumed. Carbohydrates that swiftly transform into glucose once absorbed into the bloodstream tend to be more processed and simpler to digest. When blood sugar levels increase, insulin helps muscles absorb glucose and instructs the liver to transform this glucose into glycogen. In healthy people, roughly 10-20 percent of the glucose in the bloodstream is utilized, while Taubes notes that the liver converts 30 to 40 percent into triglycerides, which are subsequently carried by lipoproteins to be stored as fat. Insulin enhances the function of LPL in fat cells, promoting the uptake and transformation of fatty acids from the blood into triglycerides inside the cells, and also inhibits the release of these fatty acids back into the circulation. Fat tissue expands as a result of fat accumulation. Insulin predominantly channels excess calories into our body's fat reserves in response to carbohydrate intake. The insulin's impact must subside before the calories in question can be used for energy.

Progress in understanding metabolic syndrome has been accompanied by the recognition of increased insulin levels and the state of insulin resistance.

Gary Taubes proposes that the primary factor contributing to weight gain is associated with consuming carbohydrates and sugars, an idea that became popular following research that started in the 1960s subsequent to the development of the first accurate technique for measuring insulin levels in human blood. Gary Taubes makes a compelling argument that insulin is closely associated with the development of obesity and diabetes, emphasizing the significant influence that carbohydrates exert.

He first discusses the early research, which confirmed what physicians had known for a century: diabetics require insulin, not only because they lack it, but also because insulin has a variety of well-documented effects on hunger, metabolism, and fat accumulation in the body.

In the late 1950s, Rosalyn Yalow and Solomon Berson at the Bronx Veterans Administration Hospital pioneered a method that enabled the accurate measurement of insulin and the evaluation of cholesterol and lipoproteins in human blood. Taubes emphasizes the significant contributions to biological and medical science made by Berson and Yalow, leading to Yalow being honored with the prestigious medical Nobel Prize in 1977.

In the year 1960, the innovative technique developed by Yalow and Berson was utilized to examine the blood samples of patients identified with the condition now known as Type 2 or non-insulin-dependent diabetes. The investigation revealed that, rather than having a scarcity of insulin, these individuals exhibited considerably elevated insulin concentrations in their blood when compared to those in good health. Individuals with diabetes often require an increased amount of insulin to elicit the expected bodily reaction.

Insulin resistance implies that the impact of insulin can differ among various tissues, resulting in a spectrum of consequences. Yalow and Berson suggested that in adults suffering from type 2 diabetes, although fat tissue remained sensitive to insulin, the responsiveness of muscles and internal organs to the hormone was diminished.

This in turn would be confirmed over the next decade, primarily by the work of the Stanford diabetologist, Gerald Reaven, who meticulously traced the connection from the body's reduced ability to respond to the action of insulin to a condition characterized by elevated blood fat levels, a term originally coined to denote a rise in triglycerides, which Reaven linked to heart disease, diabetes, and obesity. Taubes argues that a significant number of individuals experience elevated triglyceride levels due to insulin resistance and the consumption of carbohydrates, which calls for a dietary regimen that minimizes carbohydrate consumption, especially since elevated triglycerides are acknowledged as a contributing factor to heart disease.

During the annual meeting of the American Diabetes Association in 1988, Reaven presented the idea of a cluster of disorders frequently accompanying Type 2 diabetes and obesity in his Banting Lecture. Initially termed "Syndrome X," now more widely recognized as metabolic syndrome, the condition is characterized by irregular insulin release, resistance to insulin, elevated blood sugar levels, heightened triglyceride concentrations, diminished levels of HDL cholesterol, and increased arterial pressure. Reaven observed that, although there was initial doubt, the concept is consistent with the existing experimental evidence. Reaven and his team proposed that the core of these metabolic problems was obesity, which they associated with consuming too many calories in general, leading to higher insulin levels, a perspective that differs from the belief that diets high in carbohydrates are the main cause of elevated insulin levels. Taubes observes that the idea of attributing health issues to the overconsumption of carbohydrates has vanished from the core tenets of conventional medical wisdom.

Practical Tips

• Explore citizen science projects related to biology and medicine to contribute data or observations that can aid in scientific research. By participating in these projects, you can help gather valuable information that researchers may use to understand biological patterns or medical conditions, similar to how insulin measurement has advanced medical science.

Other Perspectives

• Insulin resistance and hyperinsulinemia are often consequences of obesity and metabolic syndrome, but they may not necessarily be the initial cause; the relationship could be more complex and bidirectional.
• The thermic effect of food (TEF), which is the energy expended during digestion, is higher for proteins than for carbohydrates, suggesting that diets higher in protein could potentially help in weight management, challenging the focus on carbohydrates alone.
• Some populations with high carbohydrate diets, such as those in certain Asian countries, have historically had low rates of obesity and diabetes, indicating that carbohydrates per se are not the sole determinant of these conditions.
• Additionally, the management of diabetes often involves more than just addressing insulin levels. It typically includes a comprehensive approach that considers diet, exercise, and sometimes other medications that improve insulin sensitivity or have other glucose-lowering effects.
• The relationship between insulin levels and Type 2 diabetes may vary among individuals, with some exhibiting normal or only slightly elevated levels, especially in the early stages of the disease.
• The statement might oversimplify the condition by implying a uniform response among individuals with insulin resistance, whereas there is considerable variability in how different people's tissues respond to insulin.
• Some studies suggest that inflammation may play a role in heart disease, diabetes, and obesity, independently of insulin resistance and blood fat levels.
• The definition and diagnostic criteria for metabolic syndrome have evolved over time, and different health organizations have proposed varying criteria, which can lead to inconsistencies in diagnosis and management.
• The relationship between calorie consumption and obesity is complex and can be influenced by the type of calories consumed, not just the amount; for instance, calories from different macronutrients have varying effects on satiety, metabolism, and energy expenditure.

Studies on anorexia and diabetes have shed light on how insulin contributes to the increase in body weight.

After World War II, the dominant belief was that weight gain associated with insulin was not a direct result of the hormone itself, but rather a consequence of increased consumption of food as a compensatory response to hypoglycemia induced by external factors. Taubes points out that elevated insulin levels were traditionally thought to contribute to weight gain and common obesity exclusively in the rare circumstance of hypoglycemia. He regards this determination as lacking both reason and justification.

Following the discovery of insulin, it was noted by medical professionals that insulin treatments caused both dogs with diabetes in research settings and human patients with the condition to gain weight easily, regardless of whether they were already overweight. Doctors began treating underweight children with insulin shots, which proved to be a highly successful method for helping them increase their body weight. Taubes proposes the possibility that such children could be diagnosed with anorexia. During the 1920s and 1930s, a number of medical practitioners recorded their efforts to induce weight gain in underweight individuals, including both children and adults, by administering insulin injections, which consistently resulted in similar effects. The intake of foods rich in calories and carbohydrates resulted in an increased appetite, weight gain, and a growth in fat storage. In 1933, Erich Grafe, a renowned endocrinologist at the University of Würzburg, characterized insulin as extremely potent in facilitating an increase in body weight. Taubes highlights how the American obesity research community has neglected these findings. The idea that elements beyond simple overconsumption and inadequate control of hunger could impact weight gain was considered unorthodox and possibly irresponsible.

Other Perspectives

• Weight gain in patients with diabetes may also be due to the recovery from a catabolic state (where the body breaks down tissue for energy) to an anabolic state (where the body builds up tissue), which can occur once blood sugar levels are stabilized with insulin therapy.
• Insulin shots may indeed help underweight children increase body weight, but this approach should be monitored carefully as it could potentially lead to hypoglycemia if not managed properly.
• Physical activity levels can counterbalance the intake of high-calorie and carbohydrate-rich foods by increasing energy expenditure, which can prevent weight gain.
• The historical context of insulin's discovery and its initial observations in weight gain may not directly translate to the current understanding of obesity, which is based on a much larger body of evidence and research methodologies.
• The use of insulin injections to diagnose anorexia could pose ethical concerns, as it involves administering a hormone with significant metabolic effects that may not be justified in the absence of diabetes or another medical indication.
• Genetic factors are also recognized as playing a crucial role in determining an individual's propensity to gain weight, which is not solely a result of overconsumption or hunger control.