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Let’s say you want to follow a low-carb diet, how low should your carb intake be?

The physiological response is the reference, not the SAD Diet

Defining a «low-carb diet» is is not an arbitrary decision. It is nonsense saying that a diet where 40% of the calories come from carbs is low-carb, just because those are less carbs than the 50-55% of the SAD diet (Standard American Diet). Low-carbers don’t use the SAD diet as a reference. The reference is physiological: being able to burn your own fat, or not. Losing your extra weight or not.

Some people say a diet with 40% calories from carbs is a low-carb diet, but it is as sensible as saying that your car is a racing car because it is faster than mine.

If you watch the graphs in this post, you will see that for most of us weight loss (and therefore fat-burning) happens in the range 0-100g carbs/day but probably not with more carbs/day. If the carb intake is below 50g/day the concentration of ketones in the blood are markedly increased, a condition known as ketosis. Carb intakes lower than 30g/day are currently used as a therapetic approach for different pathological conditions (see).

Low-carb experts propose the following definitions (see):

Diet/Carb content	Carbs (g/day)	% (2000 Cal diet)
Very low-carb ketogenic	<30	<6%
Low-carb ketogenic	30-50	6-10%
Low-carb	50-130	10-26%
SAD diet	250-275	50-55%

How many carbs should I eat?

In my opinion, it is more a question of quality and not so much about quantity. Avoid foods that are harmful for your health, then add to your diet fats and protein but also nutritious foods that have a few carbs like lots of green «leafy» vegetables, a few nuts and may be a probiotic like kefir or bifidus yoghourt. How many carbs do you have so far? Not a lot, I guess. Can you eat that way and see how it works for you? My point is that if you avoid grains, bread, pasta, potatoes, pizza, sugar, processed foods, etc. automatically your total carb count will fall into the low-carb zone. You just need to be a little carb-conscious with the food you eat and you are ready to find out what are the amount of carbs/day that suit your goals.

Avoid foods low in carbs, unless they are healthy. Quality matters.

Another reference

Mark Sisson suggests the following ranges as a reference:

• 0-50 grams/day – Ketosis and Accelerated Fat Burning
• 50-100 grams/day – Effortless Weight Loss
• 100-150 grams/day – Maintenance Range
• 150-300 grams/day – Steady, Insidious Weight Gain

Further reading:

• The Primal Blueprint Carbohydrate Curve
• How low is low carb?