Too much protein can lead to weight gain
Whether it’s TikTok influencers, the self-styled health gurus in your local Facebook group or your personal trainer, anyone looking to lose weight will likely be advised to eat more protein.
Yet, Lamming says, new research is suggesting that the opposite is true, as low-protein diets reprogram our metabolism in a way which promotes the burning of body fat and calories, even while we’re at rest.
He has shown this through various experiments using lab mice, where the rodents were given low and high-protein diets. The mice getting less protein became leaner and had better blood sugar control, even though they were eating more overall. On the other hand, while the rodents consuming higher protein were more satiated, they tended to gain more weight.
There is a biological explanation for this. Other scientists have found that when people get less than 10 per cent of their calories from protein, the liver starts to produce larger amounts of a hormone called FGF21. This acts on the brain, causing your body’s energy expenditure, or the total number of calories it’s burning, to increase.
“People eating a low protein diet don’t feel as full, so they eat more calories,” says Lamming. “But they still lose weight, and they lose fat mass in particular. This is due to the fact that the body’s energy expenditure seems to increase.”
Does the type of protein matter?
There are also suggestions that some protein sources may be more detrimental for us than others, especially as we age.
In particular, over consuming proteins which are rich in branched-chain amino acids (BCAAs) leucine, isoleucine and valine, has been linked to obesity, type 2 diabetes and other metabolic diseases, while restricting them appears to help ramp up metabolism and improve blood sugar control.