Hello,

I still can't find any sources for the mentioned carbohydrate intake of 120-150g. I am a nutrition advisor, and in school, we were taught that the brain requires approximately 120-130g, naturally, this amount is average and indicative. However, if we are to base our meal plans on some figures, then the mentioned amount of 120-150g does not fall into the low-carb zone but merely represents a reduction in daily carbohydrate intake in favor of another macronutrient, without necessarily leading to a shift from energy usage from carbohydrates to fats. Conversely, I have read that the body "switches" to using fats as the main energy source at about 100g. This issue is not elaborated on in the study materials, only the number is mentioned.

Thank you very much for your response, and have a nice day.

All the figures presented regarding the ratios of macronutrients in any diet are always indicative and primarily averaged, never reflecting the true needs of individuality, which need to be determined through practical testing. This also applies to the attempt to define general carbohydrate intake limits for a low-carb regime, where there are several perspectives and approaches derived from them:

1. It is possible to present a general range of values (i.e., 120 - 150 g, sometimes up to 180 g) - this carries a significant disadvantage in that it does not take into account the individual's body weight and level of physical activity, where these mentioned factors most influence carbohydrate needs.

2. We can calculate carbohydrate amounts relative to body weight - here, the most commonly presented range is 1.5-2.5 g/1 kg of body weight.

3. It is based on figures indicating the actual consumption of carbohydrates required to support brain function - here, the range of 120 - 150 g per day is presented, although this too does not account for the intensity of brain activity, which ultimately can result in differences in needs of up to double.

4. To determine specific carbohydrate intake values, a model can be used where foods that are reportedly not part of the diet of hunters and gatherers, such as grains, legumes, and some fruits, are excluded from the diet. Based on such a model, similar figures again emerge, although this approach is as inaccurate as the ones mentioned above (archaeological research proves that a certain proportion of grains and legumes appeared in the diet of our ancestors before the advent of agriculture...).

When reducing carbohydrate intake in this way, it is necessary to increase the proportion of fats as an energy source to the level required by the individual (weight reduction vs. balanced energy balance vs. weight gain), always maintaining a reasonable range of protein amounts. Metabolism, within adaptive processes, will have no choice but to adapt to this change, and due to differences in the metabolic profile of each person, the result will always be different. The carbohydrate intake threshold necessary for "switching" to the keto mode is not and cannot be fixed, as ketone bodies are produced in the body under many circumstances, and carbohydrate intake is not the only determining criterion, as is often stated. Moreover, it is necessary to distinguish between a classic keto diet and a low-carb way of eating, where in keto mode, the carbohydrate intake is much more stringent.

Themes:  Fats   Low carb   Carbohydrates   Ketogenic diet   Diet