Weight loss doctor: Nutrient ratios, not just carbs, determine fat vs. muscle loss

Weight loss physician Hsiao Chieh-chien emphasizes that the common belief that eating rice or noodles leads to weight gain is a misconception. He clarifies that while carbohydrates can be converted to fat, the body's process is indirect. Fat, on the other hand, is directly stored as body fat with minimal processing.

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The carbohydrates you eat in excess, if not used through exercise, will keep the muscle's warehouse full and make it difficult to eliminate.

The body has two main storage sites for carbohydrates: the liver and muscles. Liver glycogen acts like a checking account, readily converted to glucose to fuel the brain and the rest of the body. The brain consistently requires about 100 to 120 grams of glucose daily, regardless of a person's weight. If carbohydrate intake falls below this level, the body may break down muscle tissue to produce glucose.

Muscle glycogen is described as a private savings account, usable only by the muscle itself during physical activity. Therefore, sedentary activities do not deplete muscle glycogen stores. Carbohydrates consumed beyond the body's immediate needs and glycogen storage capacity are what eventually get converted into fat. Hsiao suggests that for "medium-carb days," maintaining intake around 100 to 120 grams of carbohydrates is sufficient to fuel the brain, roughly equivalent to two bowls of brown rice.

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The liver's glycogen is like a checking account: it can be withdrawn at any time, converted back into blood sugar, and sent to feed the brain and the entire body.

On "high-carb days," typically involving exercise, the amount of carbohydrates needed increases. For example, an hour of upper body weight training might deplete 20 to 40 grams of glycogen, while an hour of moderate-intensity cardio like running or cycling could deplete 50 to 80 grams. Hsiao recommends adjusting carbohydrate intake accordingly, suggesting around 150 to 200 grams (about three bowls of rice) for high-carb days, correlating to roughly three times the body weight in grams.

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Muscle glycogen is like private savings: it cannot be converted back into blood sugar to support others; it can only be used by that muscle when it exerts itself, which is through 'exercise'.

"Low-carb days" are designated for "inventory clearance." By significantly reducing carbohydrate intake and lowering insulin levels, the body shifts into a "fat-burning mode," converting stored fat into ketones and improving insulin sensitivity. However, Hsiao cautions that during low-carb days, adequate protein intake is essential to prevent the body from breaking down muscle for glucose. He also suggests incorporating 5 to 10 cc of MCT oil per meal to accelerate ketone production and further protect muscle mass. Ultimately, while total calorie intake determines overall weight change, the proportion of nutrients, especially protein, dictates whether the weight lost is fat or muscle, shaping the final body composition.

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Low-carb days are for the body's 'inventory clearance'. When you press down on carbs and lower insulin, the body switches to 'fat-burning mode'.