Saturated fats mainly come from animal products, such as meat and dairy. Many fast foods are high in saturated and trans fats. Trans fats make food crunchy, but are not healthy for your heart.

Several studies have found that people who ate diets high in foods such as processed meat, fried food and refined cereals were more likely to experience depression. Those who ate a healthy diet rich in vegetables, fruits and fish experienced fewer symptoms of depression.

Other preservatives you might find in your fast food include silicon dioxide, glycerin, propylene glycol and high fructose corn syrup.

If you eat junk foods that are high in empty calories, fat or sugar, it can affect your exercise performance. You may have less energy and a slower metabolism, which can lead to weight gain.

Many fast food restaurants offer side dishes that can be healthier, such as baked potatoes, yogurt and salad. If the restaurant offers a grilled meat option, choose that over fried meat.