Macro partitioning
An acute increase in dietary fat (from 20% to 50% of energy) for two days increases whole-body fat oxidation and shifts skeletal muscle metabolism toward oxidative capacity in both lean and obese humans.
If you eat more fat for a couple of days, your body will naturally burn more of that fat for fuel, even if you are obese. This adaptation happens quickly (within 24-48 hours) and works similarly for lean and obese people. However, because this study was isocaloric (same calories), simply eating more fat without reducing other calories will still lead to fat storage because the body stores the excess energy.
In response to an isoenergetic increase in dietary fat, whole-body fat oxidation similarly increases in LN and OB, in association with a shift towards oxidative metabolism in skeletal muscle, suggesting that the ability to adapt to an acute increase in dietary fat is not impaired in obesity.
Why this rating
Randomized crossover design with room calorimetry and muscle biopsies, though limited to a short duration (2 days) and small sample size.
Source
Increasing Dietary Fat Elicits Similar Changes in Fat Oxidation and Markers of Muscle Oxidative Capacity in Lean and Obese Humans
Audrey Bergouignan et al. · PLoS ONE · 2012
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