Eating very few carbs and more fats for 12 weeks doesn't improve the maximum oxygen your body can use during exercise in people with excess body fat when measured in absolute terms.

Scientific Claim

Very low-carbohydrate high-fat diets do not significantly improve peak aerobic capacity (VO2peak) in absolute terms in overfat adults after 12 weeks of intervention.

Evidence Quality Assessment

Claim Status

appropriately stated

Study Design Support

Design supports claim

Appropriate Language Strength

definitive

Can make definitive causal claims

Assessment Explanation

The study clearly measured absolute O2peak values and found no significant changes, which is accurately described as 'does not significantly improve'. The distinction between absolute and relative O2peak is properly noted.

Source Excerpt

“The absolute O2peak values did not change in any study group. However, the relative O2peak (ml/kg/min) increased in the HIIT, VLCHF+HIIT, and VLCHF groups due to body mass reduction.”

Evidence from Studies

Supporting Evidence (1)

Why it supports

The RCT design with four groups shows no significant changes in absolute O2peak values across all groups, while relative O2peak increases were attributed to body mass reduction rather than true aerobic capacity improvements.

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

Supported

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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