the basic and comman answer of this question is that we eat food to live well and healthy.
healthy food give nutrition , vitamens ,etc..
healthy eating affect mental and emotional health.
Choose healthy carbohydrates and fiber sources, especially whole grains, for long-lasting energy. Whole grains are rich in phytochemicals and antioxidants, which help to protect against coronary heart disease, certain cancers, and diabetes.
Eating more fruits and vegetables, cooking meals at home, and reducing your fat and sugar intake, on the other hand, may help to improve mood and lower your risk for mental health problems.
Water helps flush our systems of waste products and toxins, yet many people go through life dehydrated—causing tiredness, low energy, and headaches. It’s common to mistake thirst for hunger, so staying well hydrated will also help you make healthier food choices.