- The first documented low-carbohydrate diets became popular in the 1960s. In 1967, Dr. Irwin Stillman published The Doctor's Quick Weight Loss Diet, instructing consumers to adopt a high-protein, low-carbohydrate and low-fat diet. Others included the Air Force Diet, the Drinking Man's Diet and Austrian physician Wolfgang Lutz's Leben Ohne Brot (Life Without Bread). In 1972, Dr. Robert Atkins published Dr. Atkins' Diet Revolution. Dr. Atkins' theories became quite popular, but also drew criticism from the mainstream medical community. Opponents of Atkins' theories were cautious of the dangers of excessive fat or protein. Other diets included the Stone Age and the Scarsdale diets. In 1981, Dr. David Jenkins came up with the glycemic index, which measured the effects of foods on blood sugar levels.
- In the 1990s, Robert Atkins published Dr. Atkins' New Diet Revolution with some changes. Here he placed greater emphasis on the difference between good carbohydrates (sugary green vegetables, high antioxidant fruits) and bad carbohydrates (sugary white bread, sugary cereals). Dr. Atkins also referred to his diet as "controlled carb" rather than "low carb." Yet the principles remain the same. Dr. Atkins made the argument that restricting carbohydrate consumption could boost metabolism, inducing ketosis (low insulin levels), causing the body to burn more calories. He instructed dieters to monitor their carbohydrate intake by counting Net Carbs (consumed carbohydrates minus grams of fiber and sugar alcohols). There are four phases to the Atkins Diet: Induction (restricted to proteins and allowed vegetables), Ongoing weight loss (gradually re-adding foods such as berries, nuts and whole grains), Pre-Maintenance and Lifetime Maintenance.
- Besides weight loss, followers of restricted carbohydrate diets report a number of benefits including lower insulin levels. In a Stanford Medical School study, postmenopausal women were divided into two groups, one with a 60-percent carbohydrate diet and the other with a 40-percent diet. In the fasting state, the plasma insulin and the triaglycerol concentrations were higher in the 60-percent group. Other reported benefits of restricted carbohydrate diets include increased HDL (good) cholesterol and decreased blood pressure. Some users also report improved gum health, fewer sugar cravings, less "brain fog" and increased energy.
- Yet restricted carbohydrates are still a subject of controversy in the medical community. The American Heart Association argues that "Eating large amounts of high-fat foods for a sustained period raises the risk of coronary heart disease, diabetes, stroke and several types of cancer." The American Heart Association argues that many low-carbohydrate diets are nutritionally imbalanced. Many of these diets overemphasize meat, cheese and eggs, which are high in saturated fat, while sacrificing fruits, vegetables and whole grains. The American Heart Association also points out that these diets often result in higher consumption of sodium while reducing calcium, potassium and magnesium. The Association further argues that much of the early weight loss of low-carbohydrate diets is only the loss of water weight.
- The Atkins company responds to the American Heart Association's concerns with several counterarguments. Atkins argues that bad cholesterol will not go up because the body has switched from sugar metabolism to fat metabolism. The company also points to studies linking high-carbohydrate diets to elevated triglycerides and lowered HDL and low-carbohydrate diets to lower triglycerides and higher HDL, factors in determining risk of heart disease. The company addresses the claim that the diet is only effective because it is calorie restricted. Atkins argues that if calorie consumption is restricted, it is because sugar and carbohydrate cravings decrease under the Atkins Diet.
