How Low is Low?

The term “low” in the context of “Low-Carb” does not refer to any specific number or quantity, but rather is interpreted relative to the entire diet, or to the prevailing/current diet. In the 40:30:30 recommendation of the Zone diet, the 40 refers to 40% carbohydrate, which is higher than the 30% fat and 30% protein, but is low relative to the national recommendation for 55-60% carbohydrate. The ≤20 grams/day of carbohydrate recommended during the Induction Phase of the Atkins diet would be ~6% of a 1400 calorie diet, and an even smaller proportion of a higher calorie diet (the Atkins diet has no specific caloric guideline, although most people trying to follow the diet report consuming a calorie level lower than their pre-diet intake level).

Several examples exist worldwide of indigenous cultures that have traditionally consumed extremely low carbohydrate intakes while maintaining good health, such as the Maasai and Innuits. In some cases a minimum of 100-130 grams of carbohydrate per day (~20-25% of calories in a 2,000 calorie diet) has been suggested as an important level from a metabolic perspective that would allow for efficient use of carbohydrate and fat for energy. The bottom line is that there is no consensus on the minimum, or the optimum level of carbohydrate in the diet. If you are going to try a “lower” carbohydrate diet than what you currently consume, focus on reducing or eliminating the least nutritious sources of carbohydrates, and if you replace these with other foods, be aware of the importance of choosing healthy high fat and high protein foods.