Are Low-Carbohydrate Diets an Effective and Healthy Way to Lose Weight?

Measuring belly fat

Currently, controversy exists over the efficacy of low-carbohydrate diet plans. While these plans have grown in popularity since the 1970s, many health experts suggest the diets are ineffective at best and dangerous at worst. However, a growing group of researchers believe quite differently, pointing to evidence that low-carbohydrate diets are both safe and effective. Who's right, and more importantly, what's a dieter to do?

The Genesis of Low-Carb Diets

In 1972, Dr. Robert Atkins wrote Dr. Atkins Diet Revolution. This book revolutionized segments of the diet industry, sparked a low-carbohydrate dieting craze, and stirred controversy among his peers in the diet industry.

Challenging the Calorie Hypothesis

At the time, the prevailing diet wisdom centered around the calorie hypothesis, which was really quite simple to understand: If you eat more calories than you burn, you gain weight. If you burn more calories than you eat, you lose weight.

Dr. Atkins was the first of many to challenge this hypothesis, suggesting that calorie calculations worked on the basics of simple thermodynamics, and the human body was not a simple thermodynamic machine. Instead, it was a complex biological mechanism, and the oversimplification of calories in/calories out was the reason so many people had difficulty losing weight or maintaining it by counting calories alone.

A Growing Trend

Instead, Dr. Atkins suggested one could lose weight by eating what he termed "luxurious" foods that were traditionally forbidden on a low-calorie diet. Consumers liked the idea of being able to eat steak, bacon, butter and salad dressing while losing weight, and the Atkins diet took off. For many years, Dr. Atkins was a voice in the wilderness. While followers of his diet anecdotally reported tremendous success in weight loss and maintenance provided they followed his plan as prescribed, no studies existed to back up Dr. Atkins hypothesis that it was carbohydrates, not calories that led to overfatness.

Still, Atkins persevered, and in 1992, he introduced a new generation to low carbohydrate diets when he released, Dr. Atkins New Diet Revolution. This time, Atkins was not alone. Instead, he found growing support among other physicians who had experienced success prescribing similar diets to their patients. More low-carbohydrate diets followed, including Protein Power, South Beach, and The Zone.

Body of Evidence

As low-carbohydrate diets gained popularity, studies seemed to support their efficacy. Below are just a few of the many studies with findings supporting the safety and effectiveness of low-carbohydrate diets.

Ben-Gurion University, 2008

A 2008 study at Ben-Gurion University followed 322 dieters for two years. A third of the dieters ate a low-calorie, low-fat diet. Another third ate a Mediterranean-style diet. The final third ate a low-carbohydrate diet similar to Atkins with no caloric restrictions. The study concluded that all three diets were effective, and that Mediterranean and low-carbohydrate diets provided a safe, effective alternative to low-calorie, low-fat diets.

Theories Behind Low-Carbohydrate Diets

Most low-carbohydrate diet experts suggest that these diets lead to permanent weight loss and better overall health for two reasons. Although there is debate about which theory explains the phenomenon, most researchers agree that low-carb diets are effective.

Evolution (or Lack Thereof)

In their book Protein Power Lifeplan, Drs. Michael and Mary Dan Eades explain that the earliest humans were hunter-gatherers who ate what they could hunt or forage. This most likely included leafy plant foods, small amounts of fruit, and animals. Kurt Harris, M.D., creator of the Archevore diet agrees, stating, "...the diseases of civilization are largely related to abandonment of the metabolic conditions we evolved under..." In other words, human beings today do not eat like their earliest ancestors, and not enough time has passed to allow today's humans to process the foods they currently eat.

Harris and the Eades also agree that grains and processed foods are likely causing obesity and many of the diseases of civilization, such as type 2 diabetes and heart disease. According to Harris, these diseases may be "side effects of technological and cultural changes in the way we eat and live that have occurred since the dawn of agriculture roughly 10,000 years ago, and especially in the past few hundred years."

The Drs. Eades also point out that in pre-agricultural times, humans did not eat grains, and only in the past 50-100 years have processed and sugary foods become ubiquitous as well. Therefore, they suggest, a return to a diet more similar to what hunter-gatherers ate may be the way to return to health. Since an ancestral diet consisting mostly of meat, vegetables, and occasional fruit is a low- to moderate-carbohydrate diet, this may be one of the reasons low-carbohydrate diets are effective in generating weight loss.

Blood Sugar and Insulin

The second theory revolves around blood sugar and insulin response, which author and health reporter Gary Taubes explains in his book, Good Calories, Bad Calories. According to Taubes and other experts, the following is true about insulin:

  • Eating carbohydrates causes your blood glucose levels to rise.
  • Your pancreas releases insulin in response to elevated levels of blood glucose.
  • Insulin is a fat storage hormone. When it is present in your bloodstream, it not only ushers food into storage as fat, but it prevents your fat cells from releasing any of its fat for energy use.
  • Insulin control is the key to keeping food from being stored as fat and allowing your body to access its fat stores for fuel.
  • In the presence of insulin, it is very difficult to lose weight.
  • Today's carbohydrate-laden diet keeps insulin levels elevated in the bloodstream, which is why so many people gain weight or cannot lose it.

Low-Carb Diets

Today, you can find a number of low- and reduced-carbohydrate diets. While they are based on similar principles, their implementation may be slightly different. If you choose to pursue a low-carbohydrate diet, it is best to find one that suits your taste and then buy the book and follow its recommendations.


The grand-daddy of low-carbohydrate diets, the Atkins diet goes in phases and can be customized.

  • During Induction, eat fewer than 20 g of carbohydrates per day, plus unlimited protein and fat. Get your carbohydrates from leafy greens and fewer than 2 oz of full-fat dairy such as cheese or heavy cream.
  • In Ongoing Weight Loss (OWL), gradually increase your daily carbohydrate intake by 5 g every one to two weeks. When you stop losing weight, back off by 5 g per day and eat at this level until you achieve your goal weight.
  • In Maintenance, adjust your daily carbohydrate intake upward by about 5 g. If you begin to gain weight, back off slightly.


This is an ancestral-style eating plan that suggests you eat like your hunter-gatherer ancestors did. It includes the following recommendations:

  • Eat mostly plant and animal foods.
  • Avoid grains, particularly the gluten grains of wheat, rye, barley, and oats.
  • Avoid dairy.
  • Eliminate processed foods and seed oils.
  • Eat fruit, but not too much.

The Zone

Barry Sears created the Zone diet for peak performance and weight loss. The following are among the principles of this reduced-carbohydrate plan:

  • Eat 40 percent of your calories from carbohydrates.
  • Eat 30 percent of your calories each from fat and protein.
  • Minimize processed foods and sugar.

Medical Concerns

In spite of the evidence suggesting low-carbohydrate diets are both safe and effective, many health professionals still express concerns. According to, low-carbohydrate diets have the following risks:

  • They are high in saturated fat and may increase the risk of heart disease and certain cancers.
  • Limiting fruits and vegetables may lead to insufficient fiber intake, which can cause constipation and gastrointestinal difficulties.
  • High-protein diets may tax kidney function.
  • Low-carbohydrate diets lead to ketosis, which can cause dizziness and weakness.

Because of these concerns, low-carbohydrate diets may not be good for people with the following conditions:

  • Kidney problems
  • Gout
  • Heart disease

Talk with your doctor before pursuing any diet.

Modifying Low-Carb Diets

If a low-carbohydrate diet seems too extreme for you, you may also be able to develop a lifestyle that supports your body's natural tendencies without restricting major food groups. If you'd like to pursue a healthy diet but worry about the high levels of protein or fat and low levels of fiber associated with low-carbohydrate diets, consider the following:

  • Substitute fatty meats with lean proteins like egg whites, poultry, and fish.
  • Eliminate or minimize dairy.
  • Eat in-season fruits and vegetables.
  • Minimize grains or eat slow-burning, non-gluten grains, such as quinoa or millet.
  • Consume one ounce of nuts or seeds daily.
  • Add legumes for fiber.
  • Eat a moderate amount of protein and make up calories with healthy veggies.
  • Choose low-glycemic foods instead of low-carbohydrate foods.

Effective, Healthy Weight Loss

The best weight loss diet is one that you can and will follow. Many people enjoy the foods available on low-carbohydrate diets and thus find them easier to sustain. Studies indicate these diets are both healthy and effective if followed appropriately and that as long as you pursue a moderate-carbohydrate lifestyle without a return to previous levels of eating refined, processed foods, you can maintain your weight loss. If a low-carbohydrate diet appeals to you and your physician gives you the go ahead, give it a try. You just may wind up healthier for having done so.

Are Low-Carbohydrate Diets an Effective and Healthy Way to Lose Weight?