Low carb diets can work wonders for reducing body fat, but not everyone gets desired changes in body composition despite carb restriction. Why not?
Many low carb gurus suggest that you can eat unlimited fat and protein and still lose body fat, so long as you restrict carbohydrates sufficiently. Consequently, many people eating low carbohydrate diets eat fat very freely.
This can easily put a stop to fat loss. Here’s why.
Although fat doesn’t stimulate insulin release, if you want to burn body fat, you have to create a fat deficit—that is, you have to eat less fat than you burn daily. If you eat the same amount or more fat than you burn, you will burn only the fat you eat, not the fat on your body.
To burn off a pound (454 g) of fat each week you need to burn 65 grams of body fat every day. You won’t easily do this if you use fatty foods freely.
Imagine a 150 pound woman trying to lose 30 pounds of fat. If she is moderately active, she may expend about 1700 calories daily. On an ongoing basis, the body derives about 70% of its energy from fat, so this woman’s body uses 1190 fat calories daily, coming from 132 total grams of fat.
If she doesn’t increase her activity level substantially, to create a fat deficit of 65 grams daily, this woman will have to limit her total fat intake to no more than 67 grams per day. This will force her body to get the other 65 grams of fat from body stores.
It is easy to consume 67 grams of fat if you use fatty meats, bacon, sausages, any oil, butter, cream, coconut milk, nuts, or other fats liberally. For example:
- Fatty meats, sausages, and bacon provide at least 8 grams of fat per ounce
- Oils have 15 grams per tablespoon
- Butter supplies 11 grams per tablespoon
- Heavy whipping cream supplies 6 grams per tablespoon
- One ounce of nuts—for example, just 14 walnut halves—supplies 19 grams of fat
These quickly add up. A half pound of fatty meat would provide 64 grams of fat, completely using up the daily fat allowance for this individual. Two ounces of nuts and two tablespoons of olive oil would provide 68 grams of fat on top of what occurs in meats.
Thus, to succeed in losing body fat, most moderately active women and many largely sedentary men have to limit themselves to lean meats, vegetables, and low sugar fruits, and use nuts and added fats very sparingly. Once they achieve their desired body composition, they can eat fats more liberally.
Alternatively, they would need to dramatically increase their fat expenditure by increasing physical activity. For example, to burn up an extra 65 grams of fat daily, you would have to walk or run about 6 miles.
Reducing carbohydrate makes fat loss easier, but it can backfire if you eat too much fat for your activity level.