‘Calories in, Calories out’ — Does It Really Matter?

Different foods can affect your hormone levels in different ways.

The differing effects of glucose and fructose serve as a good example. These two simple sugars provide the same number of calories per gram, but your body metabolizes them in completely different ways.

A diet too rich in added fructose is linked to insulin resistance , increased blood sugar levels, and higher triglyceride and LDL (bad) cholesterol levels than a diet providing the same number of calories from glucose.

Your nutrient intake impacts your hunger and feelings of fullness.

For instance, eating a 100-calorie serving of beans will reduce your hunger much more effectively than eating a 100-calorie serving of candy.

That’s because foods rich in protein or fiber are more filling than foods containing lower amounts of these nutrients.

This is why most processed foods that are rich in fructose but devoid of protein or fiber generally make it more difficult for you to maintain an energy balance.

Foods affect your metabolism differently. For instance, some require more work to digest, absorb, or metabolize than others. The measure used to quantify this work is called the thermic effect of food (TEF).

The higher the TEF, the more energy a food requires to be metabolized. Protein has the highest TEF, while fat has the lowest. This means that a high-protein diet requires more calories to be metabolized than a lower-protein diet does.