If you track your calories, you may be aware of the effect food has on your metabolism. You may have also heard the statement: 3,500 calories equals 1 pound of fat. So in theory, a 500-calorie deficit per day should equal 1 pound of fat loss each week. If that is true, then eating a 500-calorie surplus every day should result in a gain of 1 pound per week. But is that of fat or muscle? Most of us realize that this formula can’t be that simple.

Working with these numbers can be confusing and frustrating, especially when we don’t see the results we expect. Unfortunately, there is so much more involved. Calories in versus calories out (energy in versus energy out) is not the only variable to pay attention to.

Macronutrients: Each of the macronutrients has a different thermogenic effect. Therefore, your body breaks down proteins, carbohydrates and fats at different rates and absorbs them differently depending on various needs.

Whole versus processed food: When a food is a processed food, the nutrients have already been broken down into a more simple form. Our bodies absorb more of those nutrients than when we eat whole foods.

Cooked versus raw: Cooking foods breaks down the nutrients, making them easier to absorb. Raw, whole foods requires our bodies to work harder to break them down— and high fiber in foods ushers them through our digestive system before being fully absorbed.

Body Type: Everybody is different. How our bodies digest and deal with our nutrition isn’t an exception. Nutrients may be treated differently in our bodies based on genetic predisposition, physiology and age.

There are more factors that may play a role. Calories reported for most foods are based on averages. Nutrient labels are legally allowed to be up to 20 percent off the actual energy output and are therefore considered highly inaccurate. How quickly a product breaks down into sugar is rarely taken into consideration. Above anything, remember that an excess of calories of any kind will primarily be stored as fat.

Calories should be used as a guideline only. Eating clean, whole foods and paying attention to portion sizes should also be part of your tracking. Food is fuel. And what you fuel your body with will determine how you look and feel. Your body is not looking for calories; it needs nutrients. So feed it what it’s asking for.