A major scientific review is challenging the idea that more protein is always better.
The review, led by pathologist and biomedical researcher Dudley Lamming and published in the journal Cell Press Blue, examined more than 350 studies involving humans, mice, insects, yeast, and other organisms.
The review found that eating less protein, or less of certain amino acids that make up protein, may turn on body processes linked to healthier aging, as well as metabolism, the process by which the body turns food and drinks into energy.
The study points to increased fat-burning activity in lower-protein diets, and from there connects those diets to lower body fat and better aging.
This isn’t a new result… carrying excess bodyfat is bad, we’ve known this conclusively for decades.
The increased use of bodyfat for energy is also expected (if you aren’t overeating). Your body has 2 fuels cells can use, glucose and ketones. Glucose is easy, and this is the primary pathway. If you eat carbs, your body converts them to glucose and feeds that to your brain, muscles, etc.
If you aren’t eating enough, your body breaks down stored glycogen in your muscles to get glucose. Once those reserves are gone, your body will switch to converting fat stores into ketones. This can be a rather unpleasant switch for a few days until you adjust.
However, there is another pathway. If you are eating significant amounts of protein, the amino acids will be used for gluconeogenesis (literally: “new glucose creation”) by your liver - turning the excess protein in your diet into glucose for your cells to use for energy.
So, if you are eating a lot of protein and otherwise not overeating calories and carbs, your body will turn that protein into glucose rather than scavenging bodyfat into ketones. Eating less protein (and more fats) would promote the fat-burning pathway and lower bodyfat overall.
The study is solid, confirms the general consensus understanding of metabolism. The reporting is trash. Don’t avoid protein. But also don’t assume 10 g/lb is doing anything to help you build muscle or lose weight - after a certain point, it’s just energy.