Carbs Are Your Friend

Nutritional fads tend to rise and fall in cycles. Remember the early ‘90s, when the popular wisdom was that fat is bad for you and everything had to be fat-free? Today, the tide has turned with the popularity of the ketogenic diet, and the common cry is that carbs are the enemy.

Fads come and go, but no matter how we look at it, the United States’ obesity rate is still climbing. Is it really just one ingredient or macronutrient that is the underlying cause? Or is it more likely a multitude of factors?

First, let’s dispel the myth that carbs are bad for you. The fact is that carbohydrates are essential to life. They are the the main fuel source that the body uses to function. There are also certain organs that prefer carbs as their main energy source, including the brain and kidneys.

Carbohydrates are a broad class of nutrients found mostly in plant-based foods. They include complex carbs, such as grains and starchy veggies, and simple carbs, such as fruit and dairy sugars. All carbs ultimately convert to simple sugars (glucose) in the body.

The presence of glucose stimulates insulin, which is your main anabolic hormone. It shuttles glucose and other nutrients from the blood into your cells to keep them fed and happy. Unused carbs can be stored in the liver and muscles or turned into fat for later use.

When the body lacks sufficient glucose, it can burn fat to create ketone bodies as an alternate energy source. The theory behind the ketogenic diet is that if you eat primarily fat and very low carbohydrates, the body switches from running on glucose to running on ketones.

The problem with ketones is that they are very acidic. Since your brain preferentially runs on glucose, switching to these acidic ketones can make you feel very sluggish and fatigued, among other “keto flu” symptoms.

There is some evidence that ketogenic diets may be beneficial for weight loss. However, the weight loss is most often water weight and muscle mass. There have also been some nutritional deficiencies noted with the diet, since fat is higher in calories than in nutrients.

Carbohydrates, however, are packed with nutrients, as long as they come from whole foods. Complex carbs include whole grains with copious amounts of fiber, vitamins, and minerals. Fruit is also full of these and other phytonutrients that can functionally benefit the body.

Simple carbs are the “sugars” that everyone demonizes. These provide a quick burst of energy for the body, which is particularly useful for athletes. But the energy burns out just as quickly, and if we don’t utilize it for physical activity, it’s more likely to be stored or turned into fat.

Whole food carbs with fiber, however, take longer for the body to break down, which provides a more even and long-term source of energy, along with a feeling of fullness that keeps you from overeating. Fiber also supports healthy digestion and promotes healthy gut bacteria.

So, are carbs the culprit behind obesity? I would say that it’s more likely a lack of physical activity, combined with a preference for simple, overly processed carbs that lack fiber and nutrients and don’t make us feel full, prompting us to eat too much.  

If you eat carbs in the form of whole foods, such as vegetables, fruit, and whole grains, you’ll be giving the body the fuel it needs — not just glucose for energy, but vitamins, minerals, antioxidants, and prebiotic fiber to keep you healthy and functioning at your best.

Sam Kramer, MS, RD, LDN, CISSN

Sam is a Registered Dietician specializing in sports nutrition, who enjoys educating people about nutrition and exercise science. He has formulated and developed nutritional supplements for Vitacost and Kroger brands as well as for NatureWise.