People often associate a shredded physique (low body fat) with strength and athleticism. While you may look like ‘you don't even lift’ with your shirt on, being shredded exudes power and physical prowess when you're bare-chested.
__
🎛But what's going on beneath those carved-up muscles?
__
🔬To find out, Mitchell and colleagues (2018) closely monitored 9 drug-free bodybuilders, who endured 16 weeks of cutting for a natural bodybuilding show.
__
🔩The researchers specifically wanted to see how anabolic hormones and resting metabolic rate (RMR) reacted to the long period of calorie deprivation.
__
📊From week 1 to week 16 (week of show):
- Testosterone dropped by 38%.
- Free testosterone dropped by a whopping 49%.
- Insulin-like Growth Factor (IGF-1, induces protein synthesis and blocks protein breakdown) dropped by 26%.
- RMR stayed the same.
- Calorie intake went from 3000 to 2780 kcal.
- Protein was at a steady 250 g per day (3.0 g/kg).
__
💪Despite the nosedive in hormones, they managed to hold on to their precious muscle pretty well (-0.7%).
__
🔬Earlier research showed a more modest decrease in anabolic hormones [Maestu 2010]. For example, in their study testosterone dropped by 15% during 11 weeks of dieting to 6.5%.
__
🔙After the physique competitions, staying at 6.5% body fat was probably not the best idea to grow additional muscle, as all of their anabolic hormones were in the gutter. However, when they bounced back to 10% BF within 4 weeks, their hormones were almost fully restored.
__
This is precisely why we recommend building muscle in a higher range of body fat, such as 9 - 14%.
__
🛬Yes, there’s an end range. At a certain body fat percentage testosterone starts to drop again, partly because more of it gets converted into estrogen.
__
🐎All in all, there’s a sweet range of body fat levels at which you can build muscle best. Anyone who wants to get higher or lower than is trying to build muscle in a sub-optimal milieu.
__
🌺Finally, looking your best at the beach doesn’t necessarily mean you’re feeling your best, in the weight room or outside.