Carbs Make You Fat
THE CLAIM
"Eating carbohydrates causes weight gain and cutting them is necessary for fat loss."
[EVIDENCE SUMMARY]
Carbohydrates themselves do not cause fat gain—caloric surplus does. While low-carb diets can be effective, they work through caloric restriction, not carb elimination. Metabolic ward studies show that when calories and protein are matched, low-carb and high-carb diets produce identical fat loss.
What Metabolic Ward Studies Show
In tightly controlled metabolic ward studies where participants live in a research facility and all food is precisely measured, researchers found no significant difference in fat loss between low-carb and low-fat diets when calories and protein were matched. This is the gold standard of nutrition research.
Why Low-Carb Diets Often Work
- Protein is typically increased, improving satiety
- Processed food (often high-carb) is eliminated
- Food variety decreases, reducing total intake
- Initial water weight loss is motivating
The Bottom Line
Carbs are not inherently fattening. What matters is total caloric balance. Choose whichever dietary approach you can sustain long-term.
Carbs and Athletic Performance
For high-intensity exercise, carbohydrates are the preferred fuel source. Athletes restricting carbs often experience reduced performance, especially in activities requiring power and speed. The brain also preferentially runs on glucose from carbohydrates.
[KEY TAKEAWAYS]
- Caloric surplus, not carbs specifically, causes fat gain
- Low-carb diets work through caloric restriction mechanisms
- Matched-calorie studies show identical fat loss across diet types
- Dietary sustainability matters more than carb content
[SOURCES] (2)
Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men
Hall KD, et al.
Comparison of Low Fat and Low Carbohydrate Diets
Gardner CD, et al.
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