How does diet affect your metabolism?

Numerous ways. Your metabolism can be affected by your diet in many ways. A poor or imbalanced diet can slow your metabolism by not providing your body with all the necessary nutrients to function. A diet high in processed foods can be more difficult to digest, taking more energy and thus affecting your metabolism. Finally, fasting or skipping meals will slow metabolism as your body tries to conserve energy.
Of course! Certain foods require energy to digest e.g. Fruits, vegetables, whole grains. These keeps the metabolism going. Some foods require minimal energyto absorb and digest. These lowers metabolism rate.
In many ways. Diet has a major effect on one's metabolism. A starvation diet has the effect of shutting down the metabolism to the lowest level as opposed to high caloric diets. Certain foods effect the metabolism more than other foods, and foods with pestiside residual etc. Have marked effect on the metabolism. Always best to have pure natural food and clean water.
Diet, exercise. First have a metabollic blood test to rule out thyroid problems, lipid problems;get into an exercise program (can be done at home, walking at a brisk pace, or joining a gym. Rather than use the term diet, you must change your behaviour for the rest of your life.
Improve. Diet could improve metabolism by secreting pancreatic hormones which helps to reduce risk of diabetes and dyslipidemia.