In recent years, the debate around carbohydrates, insulin, and their role in obesity has taken center stage in the world of nutrition. One popular theory claims that high carbohydrate intake triggers insulin secretion, which leads to fat storage and weight gain—this is known as the Carbohydrate-Insulin Model of Obesity. But how valid is this claim? Today, we'll dive deep into the science behind this controversial topic and explore why the simplistic notion of "insulin makes you fat" may be misleading. The Insulin-Carbohydrate Connection: Myth or Fact? The Carbohydrate-Insulin Model suggests that insulin, a hormone released after consuming carbohydrates, drives fat storage. This theory is based on the fact that insulin is lipogenic (i.e., it encourages the storage of fat) and lowers blood sugar levels, potentially triggering hunger. However, despite some theoretical support, real-world evidence pokes holes in this idea. Theoretical Problems with the Carbohydrate-Insulin Model While insulin does play a role in fat storage, it doesn’t tell the whole story. Insulin’s role is anabolic—it builds up tissues by shuttling nutrients into cells, including muscle and fat. The catch? Insulin can’t lead to weight gain without a calorie surplus. In other words, unless you’re consuming more calories than you’re burning, it’s nearly impossible for insulin to create net body fat gains. Endogenous and exogenous insulin have distinct effects on hunger hormones. Endogenous insulin, produced naturally by the body, tends to help regulate hunger by promoting a feeling of fullness. In most cases, it doesn't lead to a noticeable increase in hunger levels. On the other hand, exogenous insulin, which is injected or administered externally, can cause a sharp drop in blood sugar, triggering a rebound effect that stimulates hunger. This distinction is crucial because many people mistakenly believe that all insulin spikes drive hunger, when in reality, it's primarily the exogenous form that creates this feedback loop. Another problem with the model is that it ignores dietary fats, which are often consumed alongside carbohydrates. Foods like pizza and ice cream are high in both fat and carbs, making them highly lipogenic—yet these are the foods most associated with weight gain, not simple carbohydrates like fruits or whole grains. Real-World Evidence: Carbs vs. Fats In controlled studies, researchers compared high-carbohydrate, low-fat diets to high-fat, low-carbohydrate diets. The results? As long as calorie intake is the same, both diets lead to similar weight loss or gain. This means that insulin spikes from carbohydrates don't result in more fat gain compared to fats themselves. So, what actually causes weight gain? Overeating, especially on highly palatable and calorie-dense foods, regardless of whether they are high in carbs or fats. Most lipogenic foods aren't even high glycemic index (GI) foods! Pizza, ice cream, and cookies are loaded with fat and have moderate or low GI, which means they don’t spike blood sugar as much as people assume. Also, certain foods known to be insulinergic, like yogurt, skim milk, etc., do cause a spike in insulin, but they are unique in that they don’t lead to a subsequent drop in blood sugar. This is because the body counteracts the insulin spike with glucagon secretion. Glucagon, a hormone that raises blood sugar, signals the liver to release stored glucose into the bloodstream. This balancing mechanism ensures that despite the insulin increase, blood sugar remains stable. As a result, these foods do not trigger the hunger rebound often associated with sharp drops in blood sugar, making them less likely to contribute to overeating. The Role of Palatability and Overeating Perhaps the biggest driver of obesity is food palatability. Junk foods, which are typically high in both fat and sugar, are designed to taste good, making it easy to overeat. Foods like cookies, pizza, and ice cream stimulate the brain’s reward system, causing us to eat more even when we’re not hungry. This overeating leads to excess calorie intake, which is the real culprit behind fat gain. The insulin-carbohydrate model doesn’t explain why people get fat on junk food, but the "palatability-reward hypothesis" does. According to this model, we gain weight because calorie-dense, highly palatable foods encourage overconsumption. Blaming insulin alone oversimplifies a much more complex issue. Conclusion: Insulin Is Not the Villain

Weight loss fundamentally relies on maintaining a energy balance deficit, which means consuming fewer calories than your body needs. This guide provides an easy-to-follow plan, focusing on macronutrients and calorie control to support fat loss, founded on the energy-balance model of obesity. Step 1: Estimate Your Total Daily Energy Expenditure (TDEE) To manage weight effectively, understanding your Total Daily Energy Expenditure (TDEE) is essential. The equation for calculating changes in energy storage (ΔES) is as follows: ΔES = EI - [BMR + TEF + (EEex + NEAT)] ΔES = Change in body energy storage (calories) EI = Energy intake (calories consumed through food and drink) BMR = Basal Metabolic Rate (energy needed for basic bodily functions at rest) TEF = Thermic Effect of Food (energy used for digestion and metabolism) EEex = Energy expenditure from planned exercise NEAT = Non-Exercise Activity Thermogenesis (energy expended through daily movement and activities) Calculating each component precisely can be complex, so a practical approach is to use online TDEE calculators that estimate your calorie needs based on age, weight, height, and activity level. Note that each calculators will vary slightly, so make sure to use the same TDEE calculator every time. I personally use one from KetoGains. Step 2: Set Caloric Intake for Weight Loss Once you have your TDEE, aim to create a caloric deficit for fat loss. A common recommendation is reducing calorie intake by 10-20% from your TDEE. For example, if your TDEE is 2,500 kcal/day, aiming for 2,000-2,250 kcal/day could support fat loss while minimizing muscle loss. Modifying TDEE Based on Results If you're losing weight: Continue following your current plan. If you're consistently losing weight over time without significant energy loss or hunger issues, your TDEE estimate is likely accurate. Keep doing what you're doing and monitor your progress. If you're gaining weight: Don’t immediately make adjustments if you notice a short-term increase in weight. Weight fluctuations can happen due to factors like water retention or muscle gain. Continue tracking your weight and calorie intake for at least 2 weeks. If you're still gaining weight after this period, it may indicate that your calculated TDEE is higher than your actual metabolism. In this case, reduce your TDEE estimate slightly and adjust your calorie intake accordingly. For women before menopause: Weight tracking can be more complex due to hormonal fluctuations and water retention during the menstrual cycle. These changes can cause temporary increases or decreases in weight, making it harder to assess actual progress. To account for this, track your weight consistently and compare averages across menstrual cycles rather than focusing on short-term changes. This method provides a more accurate picture of weight loss over time and helps avoid unnecessary adjustments to your TDEE based on temporary water retention. Step 3: Macronutrient Breakdown for Fat Loss After determining your daily caloric target, you can plan your macronutrient intake to optimize fat loss. 1. Protein Intake Recommendation: Consume approximately 2.2g of protein per kg of body weight daily.