Many fast foods and drinks are loaded with carbohydrates and, consequently, a lot of calories. Your digestive system breaks carbs down into sugar (glucose), which it then releases into your bloodstream. Your pancreas responds by releasing insulin, which is needed to transport sugar to cells throughout your body. As the sugar is absorbed, your blood sugar levels drop. When blood sugar gets low, your pancreas releases another hormone called glucagon. Glucagon tells the liver to start making use of stored sugars. When everything is working in sync, blood sugar levels stay within a normal range.
When you take in high amounts of carbs, it causes a spike in your blood sugar. That can alter the normal insulin response. Frequent spikes in blood sugar may be a contributing factor in insulin resistance and type 2 diabetes.
Added sugars have no nutritional value but are high in calories. According to the American Heart Association, most Americans take in twice as many sugars as is recommended for optimal health. All those extra calories add up to extra weight, a contributing factor in heart disease.
Trans fats, often found in fast food, are known to raise LDL cholesterol levels. That’s the undesirable kind of cholesterol. It can also lower HDL cholesterol. That’s the good cholesterol. Trans fats may also increase your risk of developing type 2 diabetes.
- See more at: http://www.healthline.com/health/fast-food-effects-on-body#sthash.ERUMhmGm.dpuf