Over the past decade or two, carbohydrates have been demonized for their presumed role in the growing waistlines of Americans. Consequently, “low-carb” diets, such as the Atkins Diet, emerged to combat the intake of carbs. The problem with this line of reasoning is that, although consuming excessive amounts of simple carbohydrates can cause weight gain, not all carbs (especially complex carbohydrates) are inherently bad. In fact, carbs are the body’s primary and preferred source of fuel. So, eliminating or severely restricting them is bad for your body and for your physical and mental performance.
To understand which ones to consume and which ones to avoid, one must first understand that there are two primary types: simple carbohydrates and complex carbohydrates. Second, one must understand that maintaining reasonably stable blood sugar levels is an important factor in maintaining stable energy levels and preventing undesirable weight gain.
Simple carbohydrates are simple sugars, like glucose and fructose. They are digested and absorbed into the bloodstream quickly, giving the body a quick energy high. Unfortunately, simple carbs can produce a corresponding energy low, potentially leading to hunger cravings and excessive eating. Certain simple carbs provide necessary fiber, vitamins, and minerals and are part of a healthy diet. Certain other simple, refined carbs do not provide appropriate nutrition and are not part of a healthy diet.
Healthy Simple Carbohydrates:
Simple carbs found in foods such as fruit, berries and milk contain necessary fiber, vitamins, and minerals and are part of a healthy diet. The fiber found in fruits slows the rate of absorption, helping to maintain stable blood sugar levels. (See The Importance of Fiber)
Unhealthy Simple Carbohydrates:
Simple carbs found in highly refined products such as cakes, candy bars, cookies, and other refined sugar products lack fiber, vitamins, and minerals and are not part of a healthy diet. It is important to avoid simple carbohydrates deficient in any nutritional value. These sources of empty calories contribute significantly to weight gain and ultimately to obesity. (See Stay Away from Sugar Refined Sugars)
Complex carbohydrates are long strands made up of many simple carbs. In order to be digested, they must be broken down over time. Therefore, complex carbs take longer to absorb into the bloodstream providing a longer-lasting energy supply resulting in reduced hunger cravings. Complex carbs are found in many plant-based foods, vegetables, whole grains, and low-fat dairy products.
In an ideal diet, a majority of one’s carbohydrate intake should come from complex carbohydrates (vegetable and whole-grains). Simple carbohydrate sources like fruits should be a smaller but nonetheless important part of that same ideal diet, providing important fiber as well as short-term energy (our body’s need this as much as long-term energy). (See The Importance of Fiber)
One should avoid simple carbs like cake, candy bars, cookies, and other baked goods as well as highly refined carbs like white bread and white pasta.
Approximately, 55 to 65% of your diet should come from carbs. This percentage equates to roughly 300 to 350 grams of carbs or 1200 to 1450 calories of carbs based on a 2200 calorie diet. A vast majority of carb consumption should come in the form of complex carbohydrates (whole-grains, vegetables). Avoid simple carbohydrate sources (sugars) with the only exception being fresh fruits.
How does one know how much consuming a specific food will raise glucose levels? The Glycemic Index and Glycemic Load of a food tells you how much that food effects blood sugar levels. See EMG’s Glycemic Index Chart and Glycemic Load Chart for a full list of common foods and their respective values.
EMG’s Nutrition Homepage: How to Eat Healthy
External Resources: Harvard Health: Carbohydrates