Calories are not everything: Why nutrient-rich meals are more important

You have probably often heard the phrase: "A calorie is a calorie." For a long time, this was the dominant perspective in nutritional science. What matters is only how many calories we consume—not where they come from. However, our body thinks differently.

A new study now impressively shows: Not the amount of calories decides about how we feel, how we look, and how healthy we stay – but the quality, that is the nutrients, which delivers a meal.

New study shows: Our body doesn't just count calories

A new study¹, who in Cell Metabolism (Published in 2025) now shows: a calorie is not equal to a calorie. The researchers around Preston et al. examined how highly processed foods compared to nutrient-rich, unprocessed meals affect metabolism and hormone levels.

What was compared?

The scientists examined two diets. The first group ate predominantly heavily processed products: Snacks, ready meals, frozen meals, white flour products, and sweet drinks. The second group received fresh, unprocessed food like vegetables, fruits, legumes, and whole grain products.

Important: Both groups received daily exactly the same amount of calories and the same distribution of proteins, carbohydrates, and fats. The only difference was the quality of the food.

The results:

Despite identical calories, a significant difference was observed after just three weeks:

• The "processed" group gained around 1 kilogram of body fat and a total of 1.4 kilograms of weight.

• Your cholesterol levels worsened.

• An important reproductive hormone (FSH) decreased significantly.

• In the "unprocessed" group, weight, metabolism, and hormone levels remained largely stable.

These clear differences raise a crucial question: If it really only depended on the calories— how can such effects occur?

Why does the body react so differently? The difference in nutrient-rich meals

The reason lies in the way our digestive system and metabolism work. Calories are not just calories—at least not for our body.

1. Digestion speed and blood sugar

Heavily processed products are often "pre-digested": white flours, sugars, and artificial ingredients enter the bloodstream extremely quickly. This has consequences:

• Blood sugar levels rise rapidly,

• Insulin surges up,

• Fat burning is blocked,

• and shortly thereafter the blood sugar drops - cravings are inevitable.

Unprocessed foods, on the other hand, contain natural structures, complex carbohydrates, and intact plant fibers. As a result, blood sugar rises significantly slower and more evenly, insulin remains lower, and satiety lasts much longer.

2. Fiber – much more than a "filler"

Dietary fibers play a central role in our health. Because they ensure:

• slower sugar absorption and thus a more stable blood sugar course

• longer satiety because the stomach contents remain longer

• Support of the microbiome, as they serve as food for the gut bacteria.

• Production of anti-inflammatory fatty acids by the gut flora

• improved insulin sensitivity and thus less fat accumulation

In most processed products, fiber is almost completely absent. As a result, the body loses an important regulator that stabilizes hunger, metabolism, and blood sugar.

3. Micronutrients: small substances, big impact

Vitamins, trace elements, and secondary plant substances influence every metabolic process we know— from energy production to hormone formation. If these micronutrients are lacking, as is the case with many processed foods, our body operates in "emergency mode." A deficiency leads to:

• Enzymes work more slowly,

• energy production becomes inefficient,

• Inflammatory processes increase,

• the thyroid gland (the "metabolic motor") is less active

• and hunger and satiety signals are disturbed.

Unprocessed foods, on the other hand, provide exactly those micronutrients that our metabolism needs to function smoothly and energy-efficiently.

4. The energy consumption itself also differs

An often overlooked factor is the "thermic effect of food" – the energy required by the body to process food. Unprocessed, fiber-rich foods have a higher thermic effect: the body burns more energy just for their digestion. Processed products, on the other hand, are so readily available that the energy expenditure is minimal.

That means: same calories – but a different energy expenditure during processing.

In summary: A calorie from nutrient-rich food is more valuable, sustainable, and health-promoting for the body and metabolism than a calorie from highly processed products.

What does that mean for your everyday life?

The most important conclusion is: The quality of your food is just as important as the quantity – if not more. Small changes can already have big effects.

Choose fresh, unprocessed foods more often.l

• Swap white flour for whole grain options.

• Integrate vegetables, legumes, and fruits daily to increase your fiber intake.

• Rely on natural protein sources like legumes, fish, eggs, or quark.

• Prefer beverages without sugar to support blood sugar and hunger regulation.

• Cook at home more often and take your food with you for lunch.

It's not about eating perfectly. It's about shifting the balance a little each day – towards foods that support our biology and provide the necessary nutrients.  

Conclusion: Our body does not count calories – it assesses nutrients

Two meals can have the same number of calories and yet have a completely different effect on your body. Nutrient-rich foods not only provide energy - they support your cells, your metabolism, and your hormone regulation. By choosing high-quality, natural foods, you invest in your health and daily well-being.