If you prefer a specific plan with specific rules, make sure it goes with your lifestyle, which, for most guys, gets increasingly complicated in your 40s with more responsibilities at work, with your family, and maybe even with your aging parents. A vegan diet can be hard to do in a healthy way if you live a grab-and-go existence. Meal prep is going to be a challenge if you’re never home long enough to cook. Don’t just pick what worked for a friend; pick what’s likely to work with your busy, over-40 lifestyle.
People naturally lose muscle after 40, especially women after menopause. Because muscle burns more calories than fat, this can slow down your metabolism and make it harder to shake those stubborn pounds. Strength-training exercises -- lifting weights or doing body-weight exercises, like push-ups and squats -- at least twice a week can help you keep those muscles.