Bringing your BMI within advisable limits (<23) helps by

1. Preventing diabetes.
2. If you already have diabetes then it improves your sugar levels and also helps to bring down the diabetes medication.
3. Preventing blood pressure.
4. If you already have high blood pressure then it helps to better control your blood pressure and also to bring down blood pressure medication.
5. Preventing heart disease.
6. Preventing stroke.
7. Preventing certain types of cancer.
8. Preventing osteoarthritis (joint pains).
9. Normalizing cholesterol levels and normalizing deranged blood fat levels
   (lipid profile).
10. Increasing your life expectancy.
11. Making you look younger.
12. Improving your energy levels.