These formulas or tables will help you figure out how many grams of carbs to eat per day to help you lose weight. By only consuming the minimum amount of carbs you need for your activity level, you'll avoid over-consuming carbs. Once you know your grams of carbs per day, you'll want to stay below that amount by looking at nutrition labels and carb counts in recipes in order to stay below that amount.

This approach ignores types or categories of carbs — meaning you allow yourself to eat ANY type of carb as long as you eat at or below your calculated grams of carbs for the day. Of course it's better to avoid Refined Carbs (see Carb Type Strategy) for health and insulin sensitivity purposes, but it's technically not necessary for weight control purpoess ... IF you are strict about the total amount.

Here are two ways to calculate a good carbohydrate intake.

Option 1: Basic Calculation (Formula)

This calculation uses your LBM (lean body mass).

Step 1: Multiply your LBM weight by the following:

Sedentary: 0
Lightly active: 0.5
Moderately active: 1
Very active: 1.25
Extremely active: 1.5

Step 2: Add 100g

For example:

A sedentary person of any weight would end up at 100g.
A very active person with 160 pounds LBM would end up with 300g (160 x 1.25 = 200, add 100 = 300).

Option 2: Calculation Table

If you are not exercising:
Nutritional Requirement	0 (None)
If on a diet without sufficient protein (to avoid muscle breakdown)	50 g / day or higher
To avoid ketosis	100 - 140 g / day or higher

If you are exercising:
To sustain weight training	2.5 grams per work set of 30-45 seconds
Average recommendation in bodybuilding nutrition	1 - 3 grams / pound of LBM
Average recommendation by mainstream nutritionists	2 - 3 grams / pound of LBM
Average intake of endurance athletes*	2 grams / pound of LBM
Suggested intake for endurance athletes	3 - 4.5 grams / pound of LBM
Maximum for non-carb loading individuals	4 grams / pound
Maximum for carb-loading	7 grams / pound

Modified chart from http://www.bodyrecomposition.com/nutrition/how-many-carbohydrates-do-you-need.html

* Note: This is what endurance athletes report consuming; note it is lower than the suggested intake. Given that most athletes seem to perform well enough on the carbs they consume, you shouldn't feel any need to approach the 3 - 4.5 g/lb level (and one might even suspect the validity of that recommendation).