While a balanced diet and any exercise is beneficial, for optimal results you need to adjust each by age due to unstoppable biological changes (such as collagen production, bone density, testosterone in men....). On the diet front, one may need to change the amount of protein intake to maintain and / or build muscle. I encourage you to either research the changes that happen by age brackets and the dietary, supplementation, types of exercise adjustment to make to counterbalance those changes or engage with someone who already has the wisdom.