Do Low-Carb Diets Kill Muscle Gains? New Study Says It Might Be 4X Less Effective!

[Kayce]

Mark Lobliner breaks down a new study that could change how lifters approach their diet during bulking. While many swear by keto or low-carb approaches for mental clarity and fat loss, a controlled 8-week study on natural male bodybuilders found that a low-carb ketogenic diet resulted in 4X less lean muscle gain compared to a traditional higher-carb diet—despite equal protein intake and training.

Study Quick Facts: Subjects: 19 natural male bodybuilders (age 20–40)

Low-carb group (<50g carbs/day): 0.4–0.5 kg muscle gain

High-carb group (55% carbs): 2.4 kg muscle gain

Strength: Both groups gained strength equally

Fat Loss: Keto group lost more fat

IGF-1 levels: Significantly decreased on keto

Cortisol: Slightly increased on keto

Testosterone: No change in either group

Lobliner’s Take: Carbs seem essential for maximizing hypertrophy due to their effect on glycogen, IGF-1, and training intensity.

Keto might be effective for cutting, but may blunt muscle-building potential due to hormonal shifts and lower training volume.

For bulking, he recommends keeping carbs high and only dropping them during fat-loss phases.

If you go keto, exogenous BHBs may help mitigate early transition issues (like keto flu or low energy).

Community Question: Have you tried bulking on low-carb? Did it limit your gains or help you stay leaner? Let’s hear your experience.

 

[bigaustinboy]

Bullshit.

 

[Legit]

I will have to read that study because it doesn't seem true.