Low-Carb vs. No-Carb Diets

Karen Frazier
Flame grilled steak

People considering a carb controlled diet often wonder about the differences between low-carbohydrate and no-carbohydrate diets. While the underlying principles are the same, the implementation is different. How do low-carb diets stack up against no-carb diets?

History and Principles

Many low-carbohydrate diet proponents believe that human beings need to avoid refined carbohydrates, sugars, and processed foods as an evolutionary imperative. Early humans were hunter-gatherers who most likely ate foods that they could either forage or kill. Some physicians, like Kurt G. Harris who invented the Archevore Diet, suggest that the human body has not evolved to process the foods that make up the bulk of the Western diet, including multiple processed foods like pasta, baked goods, and sugary snacks. Low-carbohydrate diets that focus on animal protein and vegetables mimic the eating habits of early humans, possibly providing a healthy, more natural way of eating.

In his book, Good Calories, Bad Calories, Gary Taubes explains exactly how carbohydrate consumption affects humans. When you eat carbohydrate containing foods, your blood glucose rises. In response, your pancreas releases insulin to return your blood sugar to a normal level. Insulin is the hormone responsible for storing dietary fat in your fat cells. It also keeps that fat from leaving the cells. Why does insulin do this? Because it exists to protect our body from times of famine by storing energy for lean times. Both types of diets limit the amount of insulin your body produces.

Low Carb Diets vs. No Carb Diets: What's the Difference?

Diets in which you consume fewer than 50 grams of carbohydrates per day are considered to be low-carb. No carb diets, on the other hand, consist of zero carbohydrates. This means that you primarily eat animal protein and fat on a zero carbohydrate diet. Low-carbohydrate diets, on the other hand, allow you to eat some carbohydrate-containing foods, such as non-starchy vegetables, nuts, and moderate carbohydrate fruits. Most of the recommend low-carbohydrate diet plans, such as Atkins, Protein Power, and South Beach, recommend a moderate amount of carbohydrate intake.

Many people believe that if eating a low-carbohydrate diet will lead to weight loss, then eating a zero carbohydrate diet will bring about faster and greater losses. This isn't exactly true. Limiting carbohydrates in your diet is not the same as limiting calories and fat, and the mechanisms of loss differ. There is no scientific evidence that eating a zero carbohydrate diet will lead to faster weight loss.

Low-Carb Studies

Many scientists have studied low-carbohydrate diets to determine their efficacy. A 2010 Temple University study followed dieters for two years. One group of dieters ate a traditional low-fat, low-calorie diet while another group ate an Atkins-style low-carbohydrate diet. The study showed both diets to be equally effective at generating weight loss. Similar results have turned up in other studies, as well.

No-Carb Studies

The only study performed on a zero-carbohydrate diet occurred in 1929 when two men agreed to go a year eating only meat. The study participants didn't lose weight, but they also experienced no predicted adverse effects of too much protein in the diet such as kidney disease or vitamin deficiencies.


Many health experts, such as MayoClinic.com, express concern that low-carbohydrate diets contain insufficient fiber, which can lead to constipation or even colon disease. No-carb diets contain even less fiber. Both low and no-carb diets are also high in saturated fat, which has been shown to contribute to heart disease.

No-carbohydrate diets are an extreme form of low-carbohydrate diets. For many, they prove difficult to maintain because of the lack of variety inherent in the diet. Most experts suggest a moderate approach to low-carbohydrate dieting that includes, at the very least, non-starchy vegetables. No discernible benefits arise from fully limiting carbohydrates.

Before going on a low-carbohydrate or no-carbohydrate diet, talk with your doctor.

Low-Carb vs. No-Carb Diets