The bad reputation held by fast food has a lot of contributing factors, but the foremost issue is that fast foods are packed with sodium and trans-fats. These two substances cause a lot of damage to your body. The more you eat, the more harmful they are.
- Sodium - Fast food restaurants serve food that is legendarily high in sodium. Your kidneys’ job is to remove the salts from your body, but if you’ve consumed so much that they can’t get rid of it fast enough, the salts will build up in your system. All this accumulated sodium in your bloodstream means your heart has to work harder, which can lead to heart disease and high blood pressure. Also, putting such a burden on your kidneys can increase your risk of kidney disease.
- Trans-fats - Possibly the most dangerous substance in fast food is trans-fats. Eating a large amount of trans-fats significantly increases your risk of heart attacks, diabetes, and stroke.
- Sugar - Most people know about high fructose corn syrup in soft drinks, but few know that sugar is present in most items on a fast food menu. The average fast food burger has 10 grams of sugar, about as much as two cookies. Breakfast items on the fast food menu have even more sugar, even without the maple syrup.
- Calories - Despite being high in calories, fast food has very little nutritional value. A fast food meal can have as much as 1,500 calories, which is more than half of the daily calorie intake needed for an adult. Also these empty calories come with 75 grams of fat, and almost no vitamins.
- Offsetting good food - When you’re eating all these empty calories, you’re filling up space in your stomach that could be filled with healthier food.
- Digestive problems - Fast food takes a toll on your digestive system, and people who eat a lot of it are likely to have stomachaches and other digestive issues. GERD, or gastro-esophageal reflux disease and IBS, or irritable bowel syndrome are both conditions that could develop in people who eat a lot of fast food.
Reference:
http://www.healthline.com/health/fast-food-effects-on-body