This is my simple breakdown on how food and exercise effects the body.
A car is a machine that contains many parts that somehow must all function together to keep it functioning efficiently. The body is too like a machine, however unlike a car, the body is organic. Organic, what's that mean and how does it relate to you and I? Well for one thing, you and I are alive. In a simple scientific sense we are born, grow, develop, reproduce, and respond to our surroundings physically such as cold weather makes us shiver. Do you ever notice that too much alcohol and skipping meals makes you sleep less and feel more tired? It's not only that we will feel fatigued by a lack of food but we will also be more prone to mental problems. In order for our bodies to carry out these tasks effectively, it requires proper care of the little pieces within the body such as the blood, hormones, joints, etc.
In order to properly maintain our bodies as well as our minds we must eat balanced foods as well as exercise. Healthy food and exercise will help our bodies circulate nutrients within the body an remove unneeded waste. For example, if we eat too many bad fats can make you grow a belly. This belly is just a storage for all the excess fat because the body hasn't found a use for it nor is flushing it out fast enough. However, if we exercise too much then we will not have any fuel left to carry out our daily activities. Therefore, we must find our balance of exercise and nutrition.
Here are some previous posts on nutrition
In take and out take
Choosing a nutritionist
Healthier from quitting red meat