Hello Emma, 

Firstly, you shouldn't reduce the food you eat daily. You can change the menu and the way you eat. You will have a good health if you learn to love vegetables and fruits. Don't skip the meal, especially breakfast because it can help you get through the day. 

Secondly, spend about thirty minutes a day on physical activities. If you are busy and don't have much time to swimming or doing yoga, you can go jogging or running around the park near your house in the moring or after work. Keep practicing regularly to be always healthy.

Finally, remember not to sleep late. It's a very bad habit. Early to sleep and early to wake up helps you get more time to do morning exercise and get a nutritious breakfast.

I hope you always have good health.

Love, 

Hang.