Do Low Carb Diets Work?

Courtney Rayhill, RD, LD

Registered Dietitian, McCallum Place

With the recent popularity of low-carb diets it would be easy to conclude that these are a recent invention. However, the idea of restricting carbohydrates to lose weight goes back to at least 1863 and William Banting. He suggested a low-carbohydrate diet to increase optimal health and weight loss.

In more recent years we have seen the popularity of diets such as the Atkins diet (1972), the South Beach Diet (2003) as well as the more recent ketogenic diets. It is likely that most Americans can say they have either tried one of these diets themselves or know someone who has. The question is, do they deliver on their promise of lasting weight loss?

Despite the popularity of these diet plans they often do not last long or provide long-term benefits. Here’s why low carb diets are difficult to maintain, nor do they yield their “promised” results.

Low-Carb Diets Rob Your Body of Necessary Energy

Carbohydrates are the body’s main and preferred source of energy. In college, one of my professor’s favorite analogies was, “If you’re going on a road trip in your car you prepare by filling up the gas tank, so the car is fueled for travel. Carbs are to the body what gasoline is to a car; fuel.”

Carbs power everything you do from thinking, to breathing, to running, and all activities in between. If you restrict your intake, the body does not simply start breaking down fat tissue, first it turns to muscle for energy. The less muscle mass you have, the lower your RMR or resting metabolic rate is (RMR= amount of calories your body needs to keep you alive when you are, simply, sitting completely still). So, while it may appear you are losing weight by consuming less carbs, the truth is you are probably just losing water and muscle mass.

The solution: do not restrict carbs or any other macronutrient for that matter.

Carbs Are Not the Enemy

One of the biggest misconceptions behind the low-carb diet craze is the idea that carbs make you fat. This is simply not the case. The truth is there are many complex factors, including activity, genetics, meal timing, metabolism and consuming too many calories from any source, that contribute to weight gain. Carbs are not the enemy, and neither is food.

The truth: most carbohydrates come from plant-based foods. Sugars and starches (aka carbs) are naturally formed in fruits and vegetables, beans, grain products, and nuts and seeds. Not only are these foods good for supplying energy, they also provide other essential nutrients and benefits too.

Consuming Carbs Has Many Health Benefits

Here are a few of the other benefits your body reaps from eating carbs:

  • Countless vitamins and minerals are found in fruits and veggies.
  • Whole grains not only contain nutrients like vitamin E, selenium, iron, magnesium, zinc, and B vitamins, but they also supply your body with much-needed fiber to keep things…regular.
  • Beans are another great source of fiber as well as protein and B vitamins. Some of these carbs may even be helpful with disease prevention.

The bottom line is your body NEEDS carbs to function properly. They are not the enemy. They are in fact your friend and the fuel you need to power you through your day.

Reference: ADA Complete Food and Nutrition Guide; Roberta Larson Duyff, MS, RD, FADA, CFCS