What Happens If You Mix Slow Carbs With Fast Carbs?

Low-glycemic index, or slow, carbohydrates have numerous weight loss and health benefits. They can help lower your levels of low-density lipoprotein, or bad cholesterol, control blood sugar, or glucose, and make you feel full faster and for longer periods of time. High-glycemic index, or fast, carbohydrates have adverse effects on blood glucose and insulin levels and can make you gain weight. Mixing fast and slow carbohydrates can give you some of the benefits of eating a diet high in slow carbohydrates, but the more fast carbohydrates you consume, the fewer the benefits.

Fast Carbohydrates and Blood Glucose

When you consume foods high in fast carbohydrates, such as sweets, white bread, white rice and white pasta, the carbohydrates quickly convert into glucose in the digestive system and absorb into the bloodstream. The pancreas releases large amounts of insulin in response. Insulin helps signal to the cells that glucose is available in the bloodstream. As glucose is the easiest fuel for cells to convert into energy, the cells quickly absorb the glucose and use it as energy or store it as fat or glycogen, the stored form of sugar. This causes glucose levels to drop, which triggers hunger pangs and makes you likely to consume more fast carbohydrates to offset the feeling of hunger.

The Adverse Effects of Fast Carbohydrates

If you consume frequent, large amounts of fast carbohydrates, you may cause major fluctuations in your blood glucose and insulin levels. Over time, this can make insulin receptors on the cell surfaces resistant to insulin, a condition that precedes type-2 diabetes. High levels of blood sugar can also lead to plaque formations in the blood vessels, causing blood circulation to slow down. This increases the risk of blood clots.

Slow Carbohydrates and Blood Sugar

Slow carbohydrates, such as whole-grain foods, nuts, seeds, legumes and vegetables, contain high amounts of dietary fiber. Dietary fiber can slow down the rate at which food passes through your digestive system. When food lingers in your intestinal tract, this can delay the absorption of glucose into the bloodstream and help keep blood sugar and insulin at low, steady levels.

Slow Carbohydrates, Satiation and Cholesterol

A delay in the conversion of nutrients in the intestinal tract results in the small intestine being exposed to fat for longer time periods. There is a direct correlation between how long the small intestine is exposed to fat and the feeling of satiation. So, slow carbohydrates can make you feel full more quickly and for a longer time. Fiber can furthermore bind to bile acid, a molecule that aids in the digestion of fat. Fiber-bound bile acid passes through your system undigested. As bile acid derives from bad cholesterol, eating slow carbohydrates can lower your levels of bad cholesterol.

Mixing Slow and Fast Carbohydrates

You will inevitably mix some slow and fast carbohydrates when you consume food that contains carbohydrates. For example, fruit contains dietary fiber, but it also contains fruit sugar that converts into glucose very quickly. You can do a lot to lower your intake of fast carbohydrates by substituting whole-grain products, legumes and vegetables for fast-carbohydrate foods. If you regularly mix slow and fast carbohydrates, for example, by eating white-bread sandwiches that contain a lot of vegetables, you receive some of the benefits of consuming a diet high in slow carbohydrates. If the majority of the carbohydrates you consume are fast carbohydrates, however, the beneficial effects of the slow carbohydrates will be negligible.