Exercise and Fat: A Primer
Study Details
This new review examined fat metabolism during exercise, white, brown and beige adipose tissue, and how exercise changes adipose function and signalling 🔍
Here are the key findings ⬇️
Key Findings
🔥 Fat is a major fuel at rest and during moderate exercise, but its contribution falls as intensity rises
🏃 Maximal fat oxidation generally occurs around 50–65% VO₂max
📊 In 1,121 competitive athletes, maximal fat oxidation averaged ~0.59 g/min at ~50% VO₂max
🥑 Low-carb high-fat diets can rapidly increase fat oxidation, but fat requires ~10% more oxygen than carbohydrate to produce the same ATP
⚡ Greater fat oxidation therefore does not automatically translate into better endurance performance
⚪️ White adipose tissue is metabolically active, storing energy while also influencing inflammation and signalling
🟤 Brown adipose tissue generates heat, while beige adipocytes have intermediate thermogenic characteristics
🏋️ Exercise remodels white adipose tissue by increasing lipolytic capacity, vascularisation, innervation and oxidative function
❌ Human evidence does not support the idea that exercise training meaningfully “browns” white adipose tissue
☝️ Exercise also does not consistently increase brown adipose tissue volume or activity in humans
💪 Resistance training and muscle hypertrophy may indirectly reduce fat mass, although the mechanisms remain unclear
🩸 During fat loss, resistance training and adequate protein are central to preserving muscle mass
🔄 Muscle and adipose tissue communicate through exerkines including IL-6, TGF-β2 and 12,13-diHOME which can influence…
🧬 lipolysis
📈 glucose uptake
🔥 fatty-acid oxidation
🫀 metabolic health
Conclusion
Fat is therefore not simply an inert energy store: adipose tissue is a dynamic endocrine organ that both fuels and adapts to exercise ✅
Exercise can also significantly improve adipose tissue function even when changes in total fat mass are modest 🚴♂️
Reference
https://link.springer.com/article/10.1186/s40798-026-01085-y
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