While unexpected weight gain is typically attributed to high calorie intake, a sedentary lifestyle, or medication side effects, emerging health research points to another hidden culprit: nutrient deficiencies. According to medical experts, a diet high in empty calories can leave an individual simultaneously overweight and malnourished. Deficiencies in crucial vitamins disrupt the metabolism, trigger fatigue, and alter appetite cues—indirectly creating an environment ripe for weight gain.