In general, 1g of protein contains 4 calories, 1g of carbohydrates contains 4 calories, and 1g of fat contains 9 calories. However, when using this macro math, you may notice that your total calories, as sourced from your foods’ nutrition labels, do not perfectly match what you would expect given your total macros.
This difference, typically small at 2% or less, is normal, expected, and will not hurt your progress.
In this article, we’ll review the most common contributors to this difference in calories and why that difference is inconsequential so long as you’re consistent in how you track.
Calorie Reporting
Control how calories are reported throughout MacrosFirst
Common reasons why macros don’t add up to the calories
Nutrition Label Rounding
Calories on nutrition labels are often rounded to the nearest 5 calories (if <50 calories per serving) or nearest 10 calories (if >50 calories per serving). Additionally, the individual nutrients can be rounded to the nearest whole number, so 1.4g carbs could be listed as 1g. This is not a huge difference but it can introduce deltas of a few calories per food.
Fiber & Sugar Alcohol
Generally speaking, fiber has 2 calories per gram and sugar alcohol 0.24 calories per gram; however, both get totaled together and included in total carbohydrates on the nutrition label despite the fact that neither contains 4 calories like a standard carb. And not all sugar alcohols are created equally either; xylitol and erythritol, two common sugar alcohols, contain 2.4 and 0.24 calories per gram, respectively. The metabolizable energy of fiber varies significantly depending on if it's soluble or insoluble fiber. Consequently, and to make the macro math even fuzzier, US food labeling laws allow manufacturers to deduct insoluble fiber from total carbs, but only if they choose to.
Alcohol
Alcohol, sometimes called the fourth macro, is not a protein, carbohydrate, or fat and yet it contains 7 calories per gram. We help you account for this by giving you the option to convert calories from alcohol to carbs or fat whenever you log an alcoholic beverage in MacrosFirst.
Nutrition Label Margin of Error
Nutrition labels can be up to 20% inaccurate, according to the FDA guidelines. That means, for example, that a serving of Greek yogurt labeled to contain 100 calories could actually contain up to 120 calories, and its nutrition label would still be compliant. As another example, a box of crackers labeled to contain 10g of carbs per serving could actually contain 8g of carbs, and its nutrition label would still be within bounds.
MacrosFirst displays calories from nutrition labels
We understand how satisfying it is when everything adds up, that zen of perfect equilibrium between your macros logged and total calories consumed, we really do. But that feeling of contentment doesn’t correspond with greater accuracy. For example, if you were on a high-fiber diet, the use of macro math would inflate your calories. For this reason, we use the calories from the nutrition label as the data source for displaying total calories throughout MacrosFirst.
The bottom line
Some degree of fuzzy math is unavoidable regardless of whether you use macro math or the food’s nutrition label to count calories. Typically the difference between each method is 2% or less. It’s a small difference and not worth stressing over.
Making progress against your goals is best achieved by taking a consistent approach to your tracking, and stress interferes with consistency. Whether you choose to track macros vs. calories or total carbs vs. net carbs makes, it will not harm your progress so long as you stick with one approach for consistency.
Tracking calories with absolute perfection is not mathematically possible, no matter which approach you take, and absolute perfection is not necessary to achieve your goals.