Macronutrients (macros) are a trending topic in the world of health and wellness. But macros aren’t just a trend, as any balanced nutrition plan should account for the quality and number of macros you consume. This dietitian’s guide to carbohydrates is part two of a three-part series that clarifies the conversation surrounding all three macros: proteins, carbohydrates and fats.
Over the past few years, the consensus opinion on carbohydrates (carbs) has swung back and forth. Some fad diets paint them as a villain, while other sources indicate that they are a healthy and necessary nutrient for disease prevention. So, which is it?
As with all areas of nutrition, the answer is not black and white. Your health-related goals and your body’s nutritional needs are the best indicators of your carb needs. To help you better understand carbs, here is an expert-guided breakdown of everything you need to know about this all-important macronutrient:
What are Carbohydrates?
Carbs in varying amounts account for most organic matter on earth. Carbs are the starches, sugars and fibers found in fruits, grains, vegetables and milk products. At a biochemical level, carbs are molecules that consist of carbon, hydrogen and oxygen atoms.
There are various classifications of carbs, including the following:
- Monosaccharides are the smallest sugar units containing glucose, fructose and galactose. Fruit and sweeteners contain glucose. Honey and vegetables are a few examples of foods containing fructose. You can find Galactose, the beginning molecule of lactose, in dairy products.
- Disaccharides form when any two monosaccharides link together. For example, when you combine glucose and fructose, they form sucrose, which is found in table sugar.
- Polysaccharides are a chain of more than two monosaccharides. Found in starches and fiber, Polysaccharides are the most complex of the three carbs. Glycogen, an energy source stored in the muscles and liver, is a polysaccharide.
Are There Different Types of Carbohydrates?
Carbs come in two primary forms: simple and complex. The main difference between simple and complex carbs is how quickly your body digests and absorbs them. Here’s a quick breakdown of the digestion rates and food sources for both types of carbs:
- Simple carbs digest quickly and immediately send glucose (energy) into the bloodstream. They are naturally found in fruits, milk, yogurt and vegetables. They are also found in added sugars, including raw sugar, molasses, honey, high-fructose corn syrup, agave nectar and beet sugar.
- Complex carbs digest slower and steadily release lower amounts of glucose into the blood. You can find complex carbs in starch from plants. Foods high in starch include starchy vegetables (e.g., corn, potatoes, beans) and grains (e.g., oats, barley, rice). Both refined grains and whole grains are both considered complex carbs.
Grains have three layers: the bran, the germ and the endosperm. Here’s a quick breakdown of each three layers, and their nutritional composition:
- The bran is the outer shell of the grain that contains most of the fiber.
- The germ is the second layer and is rich with nutrients (e.g., essential fatty acids).
- The endosperm is the innermost part of the grain that contains the starch.
If you eat whole-grain foods, you’re consuming all the nutrients from each part of the grain. Enriched grains are often stripped of the outer two layers, which makes them much less nutritious.
Why do I need Carbohydrates?
Carbs are your body’s primary fuel source. During digestion, carbs are broken down into simple sugars and absorbed into the bloodstream. Once in your blood, they are commonly referred to as blood sugar or blood glucose. Insulin helps transport glucose to your cells for energy. Extra glucose that isn’t needed is stored in your liver and muscles or converted to fat.
Fiber, a type of carbohydrate that the body can’t digest, cannot be broken down into sugar molecules, and instead passes through the body undigested. So while there is a debate on the number of carbs your body needs, research suggests that higher fiber diets may help reduce the risk of cardiovascular disease.
Other studies have shown that diets rich in fruits and vegetables may help people maintain a healthy weight due to their bulk and fiber content. Fiber has also shown to slow the rate of digestion, which helps you feel fuller longer and potentially help lower your total daily caloric intake.
How Many Carbohydrates Should I Consume Per Day?
Current dietary guidelines recommend that 45 to 65% of your daily calorie intake come from carbs. For people on a 2,000-calorie diet, that translates to 225 to 325 grams of carbs per day. The Food and Nutrition Board of the Institute of Medicine established 130 grams of carbs per day as the minimum requirement to support bodily functions.
However, your ideal daily carb intake can vary based on your age, gender, body composition, activity levels, metabolic and endocrine health. For example:
- People who have physically demanding jobs or regularly exercise at a low-intensity may need 1.36 to 2.27 grams of carb per pound of body mass.
- Healthy adults engaging in moderate-intensity training for 60 minutes per day may need 2.27 to 3.18 grams of carbs per pound of body mass.
- Adults performing one to three hours of moderate- to high-intensity endurance exercise per day may need upward of 2.72 to 4.5 g per pound of body mass.
- For people with diabetes, the American Diabetes Association recommends 135 to 180 grams daily as a starting point.
When it comes to your diet, it’s important to experiment. Your body is unique. What works for others may not work for you. Before making any significant changes to your diet or carb intake, speak with your doctor, especially if you have any pre-existing health conditions. From there, a dietitian can then help you determine the best amount of carbs you need based on your individual needs, goals and lifestyle.