A dietary tool called the glycemic index, or GI, measures how quickly a carbohydrate-containing food is digested and converted into glucose in the body. Maintaining a steady level of glucose in your bloodstream instead of riding a roller coaster of energy peaks and troughs can have positive effects on your health, including improved weight management and reduced risk of chronic disease. Foods that rank under 55 on the GI are sometimes called “slow” carbs because they digest more slowly.
Vegetables and Fruits
Most vegetables are low GI foods, including artichokes, asparagus, broccoli, cabbage, cauliflower, celery, eggplant, all types of greens, okra, peppers, squash and zucchini. Among the starchy vegetables, peas, carrots, parsnips and yams are all slow digesting. Fruits tend to be higher in natural sugars than vegetables and so they are digested and absorbed more quickly by the body. Still, a number of fruits are considered slow carbs, including apples, oranges, peaches, pears, plums, nectarines and grapefruit.
Beans and Legumes
Beans and legumes make good choices when you’re looking for carbs that digest slowly. Those with a GI under 55 include baked beans, black-eyed peas, black beans, chickpeas, kidney beans, navy beans, lentils, soybeans and peanuts. The added advantage of these foods is that they are rich sources of plant protein if you are trying to reduce your intake of animal protein.
Types of Grains
In general, whole-grains digest more slowly than highly refined grains like white bread. The slowest-digesting grains include 100 percent stone-ground whole wheat or pumpernickel bread, wheat and corn tortillas, quinoa, brown rice, rolled or steel-cut oatmeal, oat bran, barley and bulgur. Of these, barley and oats have the lowest GI values, according to an article published in “Nutrition Research Reviews” in 2004.
Dairy and Non-dairy Alternatives
You may not think of dairy products as carbs, but these foods supply natural sugar in the form of lactose. Some slow-digesting dairy foods include skim and full-fat milk; cheeses such as Cheddar, mozzarella and cottage; and yogurt. Non-dairy alternatives like almond and soy milk are also slow-digesting, but rice milk is not.
Nuts and Seeds
With their high fat, high protein and low carbohydrate content, nuts and seeds are slow to digest. For example, walnuts, almonds, pistachios, pine nuts, hazelnuts and cashews all rank under 25 on the GI, while sesame, amaranth, squash, sunflower and sprouted seeds are under 35. Peanut butter is a slow-digesting carb, as are unsweetened pastes and butters made from low-GI nuts.