Why We Get Fat

1. Challenging the calories-in/calories-out paradigm of obesity

Obesity is not a disorder of energy balance or calories-in/calories-out or overeating, and thermodynamics has nothing to do with it.

Flawed conventional wisdom. The widely accepted belief that obesity results from consuming more calories than we expend is fundamentally flawed. This simplistic view ignores the complex hormonal and metabolic processes that regulate fat storage and energy expenditure in our bodies.

Hormonal regulation of fat. Our body fat is carefully regulated by hormones, primarily insulin, which determines how energy is partitioned and stored. When insulin levels are high, our bodies store more fat, regardless of the total calories consumed. This explains why some people can eat large quantities of food without gaining weight, while others struggle to lose weight even on restrictive diets.

Rethinking weight gain. Instead of focusing on calorie counting, we need to understand the factors that influence insulin levels and fat storage. This shift in perspective opens up new possibilities for effective weight management and challenges long-held beliefs about diet and exercise.

2. The role of insulin in fat regulation and weight gain

Insulin works to make us fatter.

Insulin's central role. Insulin is the primary hormone responsible for regulating fat metabolism in our bodies. When insulin levels are elevated, it promotes fat storage and prevents fat breakdown, effectively making us fatter.

Carbohydrates and insulin. The amount of insulin we secrete is primarily determined by the carbohydrates we consume. Eating carbohydrate-rich foods, especially those that are easily digestible, causes a rapid increase in blood sugar, triggering a significant insulin response.

Vicious cycle of fat accumulation. High insulin levels not only promote fat storage but also increase hunger and decrease energy expenditure. This creates a vicious cycle where eating carbohydrates leads to more fat storage, increased appetite, and reduced metabolism, making it increasingly difficult to lose weight over time.

3. Carbohydrates, not overeating, are the primary cause of obesity

We don't get fat because we overeat; we overeat because we're getting fat.

Reversing cause and effect. The conventional wisdom that overeating causes obesity gets the relationship backward. In reality, the accumulation of fat in our bodies drives us to eat more, not the other way around.

Carbohydrates as the culprit. The primary driver of fat accumulation is the consumption of carbohydrates, particularly refined grains, starches, and sugars. These foods cause rapid spikes in blood sugar and insulin, promoting fat storage and increasing appetite.

Individual variation. Not everyone responds to carbohydrates in the same way. Some people are more susceptible to the fattening effects of carbohydrates due to genetic factors, hormonal imbalances, or insulin resistance. This explains why some individuals can eat large amounts of carbohydrates without gaining weight, while others struggle with obesity despite efforts to eat less.

4. The myth of exercise as a weight loss tool

If reducing calories-in doesn't make us lose weight, and if increasing calories-out doesn't even prevent us from gaining it, maybe we should rethink the whole thing and find out what does.

Exercise paradox. Despite the popular belief that exercise is crucial for weight loss, research consistently shows that increasing physical activity alone has little to no effect on body weight. In fact, exercise often increases appetite, potentially leading to increased food intake.

Compensatory mechanisms. Our bodies have evolved to maintain energy balance, and they compensate for increased energy expenditure through exercise by:

• Increasing appetite
• Reducing spontaneous physical activity throughout the day
• Lowering basal metabolic rate

Focus on diet, not exercise. While exercise has numerous health benefits, it is not an effective tool for weight loss. To achieve and maintain a healthy weight, the focus should be on dietary changes, particularly reducing carbohydrate intake, rather than increasing physical activity.

5. The historical perspective on fattening carbohydrates

Until the early years of the twentieth century, physicians typically considered obesity a disease, and a virtually incurable one, against which, as with cancer, it was reasonable to try anything.

Forgotten wisdom. For centuries, medical professionals and laypeople alike recognized that carbohydrate-rich foods were uniquely fattening. This understanding was common knowledge until the mid-20th century.

Shift in perspective. The idea that fat, rather than carbohydrates, was the primary cause of obesity and heart disease gained traction in the 1960s and 1970s. This shift was largely based on flawed science and misinterpretation of data.

Rediscovering old truths. Recent research has begun to vindicate the historical understanding of carbohydrates as the primary driver of obesity. This return to earlier wisdom offers a more effective approach to weight management and overall health.

6. The flawed logic behind low-fat diets and heart disease

If dietary fat doesn't, we should have a pretty good idea what does.

Challenging the status quo. The widely accepted belief that dietary fat, particularly saturated fat, causes heart disease is based on outdated and flawed science. Despite decades of low-fat diet recommendations, rates of obesity and heart disease have continued to rise.

Rethinking risk factors. Modern research has revealed that:

• Triglycerides, not cholesterol, are a more significant risk factor for heart disease
• Low HDL cholesterol is a better predictor of heart disease risk than high LDL cholesterol
• Carbohydrate consumption, not fat intake, is the primary driver of these risk factors

Paradigm shift. A diet low in carbohydrates and higher in fat may actually be more effective at reducing heart disease risk by:

• Lowering triglycerides
• Increasing HDL cholesterol
• Improving the size and density of LDL particles

7. Metabolic syndrome: The link between diet and chronic diseases

The simplest way to look at all these associations, between obesity, heart disease, type 2 diabetes, metabolic syndrome, cancer, and Alzheimer's (not to mention the other conditions that also associate with obesity and diabetes, such as gout, asthma, and fatty liver disease), is that what makes us fat—the quality and quantity of carbohydrates we consume—also makes us sick.

Interconnected health issues. Metabolic syndrome, characterized by insulin resistance, obesity, high blood pressure, and abnormal blood lipids, is at the root of many chronic diseases plaguing modern society.

Common cause. The primary driver of metabolic syndrome is the overconsumption of carbohydrates, particularly refined grains, starches, and sugars. These foods lead to chronically elevated insulin levels, promoting fat storage and triggering a cascade of metabolic disturbances.

Broad health implications. By understanding the central role of carbohydrates and insulin in metabolic syndrome, we can address not only obesity but also reduce the risk of:

• Heart disease
• Type 2 diabetes
• Certain cancers
• Alzheimer's disease
• Other chronic health conditions

8. A paradigm shift in dietary recommendations for health

As it turns out, both Alzheimer's disease and most cancers—including breast cancer and colon cancer—are associated with metabolic syndrome, obesity, and diabetes.

Rethinking nutrition. Traditional dietary guidelines focusing on low-fat, high-carbohydrate diets have failed to address the rising rates of obesity and chronic diseases. A paradigm shift is needed to align our dietary recommendations with the latest scientific understanding.

Carbohydrate restriction as a solution. A diet low in carbohydrates, particularly refined grains, starches, and sugars, can effectively:

• Promote weight loss
• Improve insulin sensitivity
• Reduce inflammation
• Lower risk factors for chronic diseases

Embracing healthy fats. Contrary to long-held beliefs, dietary fats, including saturated fats, are not inherently harmful. In fact, a diet higher in fat and lower in carbohydrates may be more effective at improving overall health and reducing disease risk.

9. The addictive nature of carbohydrates and sugar

Sugar appears to be addictive in the brain in the same way in which cocaine, nicotine, and heroin are.

Biological addiction. Carbohydrates, particularly sugars, trigger addictive responses in the brain similar to those seen with drugs of abuse. This makes it challenging for many people to reduce their carbohydrate intake.

Physiological cravings. High-carbohydrate diets lead to:

• Rapid blood sugar fluctuations
• Insulin spikes and crashes
• Intense cravings and hunger

Breaking the cycle. Overcoming carbohydrate addiction requires:

• Gradual reduction of carbohydrate intake
• Increasing consumption of protein and healthy fats
• Patience and persistence to overcome initial cravings and withdrawal symptoms

10. Implementing a carbohydrate-restricted diet for weight loss and health

If you're not actively losing fat and yet want to be leaner still, the only viable option (short of surgery or the prospect that the pharmaceutical industry will come through with a safe and effective anti-obesity pill) is to eat still fewer carbohydrates, identify and avoid other foods that might stimulate significant insulin secretion—diet sodas, dairy products (cream, for instance), coffee, and nuts, among others—and have more patience.

Practical approach. Implementing a carbohydrate-restricted diet involves:

• Eliminating refined grains, starches, and sugars
• Focusing on protein-rich foods, healthy fats, and non-starchy vegetables
• Gradually reintroducing small amounts of carbohydrates to find individual tolerance levels

Individualized approach. The optimal level of carbohydrate restriction varies from person to person. Some may achieve their health goals with moderate carbohydrate reduction, while others may require a more stringent approach.

Long-term success. Sustainable weight loss and health improvements require:

• Patience and persistence
• Monitoring individual responses to different foods
• Adjusting carbohydrate intake based on personal goals and metabolic health
• Focusing on overall health and well-being, not just weight loss

Last updated: January 22, 2025