Even when overweight mice eat much less food, their leg muscles don’t shrink — as long as they get enough protein — showing that muscle loss isn’t inevitable during weight loss.

When overweight mice eat significantly less food, they lose body fat no matter if their diet is low in carbs, low in fat, or high in protein — the key is eating fewer calories overall.

If you're already lean and trying to lose weight, you can keep your muscle if you lift weights, eat a lot of protein, lose weight slowly, and occasionally eat more carbs.

When overweight mice eat fewer calories, their blood sugar control gets better — but if their diet is very low in carbs, their blood sugar doesn’t improve as much as if they ate more carbs.

When older male mice eat fewer calories, they tend to keep healthier muscles and energy-producing parts inside their cells—especially if their diet includes a lot of saturated fat like from lard.

Mice that exercise and eat very low-carb diets still keep their muscle and energy stores, probably because their bodies adapt to use fuel differently.