In your 30s, your hormones change and you burn 100 calories less per day than in your 20s.
1. Increase your muscle bulk
Your waistline starts to expand as your total body fat increases, and muscle mass and body water decrease. This is why you’re likely to see an increase in body weight and lose some of your youthful muscle tone, and why it’s important to increase your muscle bulk now – to promote greater fat burning during exercise and higher calorie burn around the clock.