Is OMAD a good way for women over 40 to lose weight?

Nikkiey scores every diet on three things she says matter after 40: whether it preserves muscle, what it does to cortisol and insulin, and whether you can actually sustain it. Muscle is the big one, because muscle is your metabolism and you're already losing it. She explains that your muscle can only use about 25 to 40 grams of protein at a time for muscle protein synthesis, and anything beyond that goes to energy or other processes. Even if you hit your full protein target in one meal, which she says most OMAD women don't, you get one chance to build and keep muscle instead of three or four. That speeds up muscle loss on top of the 3 to 8% per decade you're already losing, so she gives OMAD a 2 out of 10 for muscle.

On hormones, Nikkiey says going 20-plus hours without food is a massive cortisol trigger because your body reads prolonged fasting as a threat. Cortisol and insulin, she explains, are what decide where your body stores fat. Add in how hard it is to keep going and OMAD lands at 7 out of 30, the lowest score she gave.

She also puts it in context against regular intermittent fasting. A 16:8 window has the same problem in milder form: you get two or three meals to spread protein across, which can work if you're intentional, but most women end up tracking the clock instead of their protein. She notes a 16-hour fast is less stressful than a 22-hour one, yet for a woman in menopause with already elevated cortisol, it can still add stress. If menopause or blood sugar is part of your picture, talk it through with your doctor.

If OMAD has left you hungry, stalled or losing ground, the problem isn't your willpower. It's a plan that works against the muscle and hormones you're trying to protect.