Calories for Weight, Food Quality for Health - Understanding Why Even "Healthy" Diets Can Lead to Weight Gain

This paper examines the relationship between caloric intake, food quality, body weight regulation, and long-term health outcomes. Drawing on current evidence, it distinguishes between the role of total energy intake in determining short-term body weight changes (weeks to months) and the role of dietary quality in shaping long-term metabolic, cardiovascular, and overall health (years to decades). A practical 2×2 framework is presented to illustrate how caloric balance and food quality interact across real-world dietary scenarios. The paper concludes that sustainable health outcomes are best achieved through caloric balance combined with nutrient-dense, minimally processed foods, tailored to individual needs. Preprint – not peer-reviewed. English version. Version 1.0 - January 2026. A Greek version of this paper is also available.