Americans consume carbohydrates in quantities often exceeding 300 to 400 grams a day. Most of the carbohydrates in the standard American diet come from grains, starchy vegetables, sugar, fruits, yogurt and milk. The 2010 Dietary Guidelines for Americans recommend that 45 percent to 65 percent of your calories come from carbohydrates. If you consume more than your body can handle, you can start to experience some health problems.
One of the first sign of an excessive carbohydrate intake is weight gain or an inability to lose weight. Not only does an excess carb intake contribute extra calories to your diet, it also stimulates the release of larger amounts of insulin. High insulin levels help you control your blood sugar levels by shoveling the sugar circulating in your blood, which is the result of the digestion of carbohydrate-containing foods, into your cells, where it is stored as fat.
High Blood Sugar Levels
During the digestion process, carbohydrates break down into glucose, or sugar, which is then absorbed into your bloodstream. The more carbohydrates you eat, the higher your blood sugar levels rise after eating. Insulin is usually released by your pancreas in amounts that are proportional to increases in your blood sugar levels. However, with time, your pancreas may become less efficient at producing these large amounts of insulin. If you have prediabetes or diabetes, your pancreas is already showing signs of fatigue. As a consequence, your excessive carb intake could lead to high blood sugar levels and uncontrolled diabetes.
Your triglycerides should ideally be below 150 milligrams per deciliter to keep your heart healthy. Eating too many carbs is associated with higher triglycerides levels, while decreasing your carb intake can help you bring these levels back into the desirable range, according to a paper published in August 2005 in "Nutrition & Metabolism."
Low HDL Cholesterol Levels
HDL cholesterol is often referred to as the good cholesterol that protects your heart from cardiovascular diseases. Ideally, your HDL cholesterol should be 60 milligrams per deciliter or more. A high-carb diet is often associated with lower HDL cholesterol levels. In a study published in May 2004 of "Annals of Internal Medicine," the group eating a calorie-restricted, high-carb diet had a drop of 1.6 milligrams per deciliter in their HDL cholesterol levels, while the group assigned to the low-carb diet boosted their HDL by 5.5 milligrams per deciliter.
- U.S. Department of Agriculture and U.S. Department of Health and Human Services: "2010 Dietary Guidelines for Americans"
- Nutrition & Metabolism: The Case for Not Restricting Saturated Fat on a Low Carbohydrate Diet
- Annals of Internal Medicine: A Low-Carbohydrate, Ketogenic Diet versus a Low-Fat Diet To Treat Obesity and Hyperlipidemia