Is 'You Can't Bulk on Keto' True? Can You Actually Build Muscle Without Carbohydrates?

What research says

• This claim is exaggerated.
• Research including ketogenic-diet-body-composition-rct confirms that lean mass gains occur on ketogenic diets when caloric surplus and adequate protein (1.6–2.2 g/kg bodyweight) are maintained.
• Protein-intake-muscle-meta shows that the primary drivers of muscle protein synthesis are protein intake and resistance training — not insulin per se.
• Both conditions are achievable on keto.
• However, high-protein-overfeeding-rct suggests that matching hypertrophy rates seen in high-carbohydrate diets under identical calorie and protein conditions can be difficult. 'Can't build muscle' is false, but 'less efficient' has some support.

What research says

• High-protein-overfeeding-rct demonstrates that even at matched caloric surplus, high protein intake groups show significantly less fat gain and more lean mass gain — protein quantity, not calorie source, is the primary determinant of body composition outcomes.
• Keto bulking with high protein is theoretically capable of minimizing fat gain while increasing lean mass.
• Practically, however, keto's high dietary fat content makes it easy to oversupply fat calories, and failing to deliberately prioritize protein intake risks producing a fat-heavy bulk.

What research says

• The claim that 'low insulin means minimal fat gain' is oversimplified.
• Fat storage is determined by total energy balance (intake > expenditure), not insulin alone — fatty acids themselves are incorporated into adipocytes via insulin-independent pathways (e.g., acylation-stimulating protein).
• Carbohydrate-periodization-meta shows that low-carbohydrate groups do not consistently show less fat gain than high-carbohydrate groups during a bulk.
• Caloric surplus management remains the primary variable.
• Additionally, the high-intensity training limitations on keto can reduce training volume and thereby diminish hypertrophic stimulus — a meaningful risk for the keto bulk approach.