I know that one should not workout on an empty stomach. But how much food should be put in exactly? Is it okay if I just drink a glass of milk with some Bournvita/Protinex before weight training in the morning? You are right. One should not workout on an empty stomach in the morning as that will lead to fatigue and exhaustion. You need energy for optimal performance during your workout. But is drinking just a glass of milk enough? According to celebrity fitness trainer Vinod Channa who has trained stars like John Abraham and Shilpa Shetty Other than milk