Counting calories? Your body is not a simple math equation; it is a complex chemistry set.

While “calories in, calories out” is technically true based on the First Law of Thermodynamics, it’s a misleading oversimplification. The type of calories you consume directly alters the “calories out” side of the equation through the Thermic Effect of Food (TEF).

For example, your body uses 20-30% of the calories from protein just to digest it, compared to only 5-10% for carbohydrates and 0-3% for fats. Does that mean you should just eat more protein? Not necessarily as we’ll get to in a future post.

Furthermore, high-fiber calories are not fully absorbed, and different foods significantly impact hormones like insulin, ghrelin, and leptin, which regulate appetite and metabolic rate.

Research from scientists like Kevin Hall at the NIH confirms that food composition, not just calorie quantity, is a critical driver of energy expenditure and weight regulation.

Not only that, but eating ultra-processed foods can cause you to eat 500 more calories than normal according to research done by Hall.