Don't exercise too hard & put stress in your body. Eating less already give some stress mentally & physically. If you add hard exercise will give you even more stress, that's why some people couldn't do it.

My simple observation, if your lips dry most of the day mean you have stress your body too much. It should be approach slowly, without you realizing it. Eat normal but cut the portion, exercise easy to burn fat. Remember, your goal is to lose weight not to become body builder

If you are already fit. Short high intensity interval help prolong fat burning after exercise too. This way, you will not put yourself into too much stress while still maintaining your muscle growth hormone

Usually you need to find balance with exercise. Too much will make you craving for more energy. Good luck to you..