Adding high-intensity interval training to a very low-carb diet doesn't stop the muscle loss that happens when people with excess body fat eat very few carbs for 12 weeks.

Scientific Claim

Very low-carbohydrate high-fat diets combined with high-intensity interval training do not prevent lean body mass loss in overfat adults during the intervention period.

Evidence Quality Assessment

Claim Status

overstated

Study Design Support

Design supports claim

Appropriate Language Strength

probability

Can suggest probability/likelihood

Assessment Explanation

While the study shows association between VLCHF diet and lean mass loss regardless of exercise, the authors note that DXA may interpret body water loss as lean mass loss due to accelerated sodium and water excretion with low-carb diets. The causal claim should be qualified.

More Accurate Statement

“Very low-carbohydrate high-fat diets combined with high-intensity interval training are associated with similar lean body mass loss as diet alone in overfat adults during the intervention period, though this may partly reflect body water loss.”

Source Excerpt

“Total lean mass significantly decreased after 4 weeks by 4.7 [3.9; 5.7] % and 3.9 [3.1; 5.1] % in the VLCHF and VLCHF+HIIT groups, respectively. These changes remained stable over the 8 and 12 week measurements (4.2 [3.1; 5.2] % and 4.9 [3.8; 6.5] %, respectively). Exercise in the VLCHF+HIIT group did not prevent this lean body mass change.”

Evidence from Studies

Supporting Evidence (1)

Why it supports

The RCT design shows similar lean mass decreases in both VLCHF and VLCHF+HIIT groups, with no significant difference between them. The study specifically states that exercise did not prevent the lean body mass change.

60

Score

Effects of a Very Low-Carbohydrate High-Fat Diet and High-Intensity Interval Training on Visceral Fat Deposition and Cardiorespiratory Fitness in Overfat Individuals: A Randomized Controlled Clinical Trial

RCT

Overstated

⚠️ Overstated

While the study shows association between VLCHF diet and lean mass loss regardless of exercise, the authors note that DXA may interpret body water loss as lean mass loss due to accelerated sodium and water excretion with low-carb diets. The causal claim should be qualified.

More accurate phrasing:

“Very low-carbohydrate high-fat diets combined with high-intensity interval training are associated with similar lean body mass loss as diet alone in overfat adults during the intervention period, though this may partly reflect body water loss.”

Source Study

Effects of a Very Low-Carbohydrate High-Fat Diet and High-Intensity Interval Training on Visceral Fat Deposition and Cardiorespiratory Fitness in Overfat Individuals: A Randomized Controlled Clinical Trial

Score: 60

DOI: 10.3389/fnut.2021.785694

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Adding high-intensity interval training to a very low-carb diet doesn't make the belly fat reduction any better than just doing the diet alone in people with excess body fat.

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