Energy balance

A lower resting energy expenditure (REE) is a significant risk factor for future body-weight gain in individuals who are not obese.

If you struggle with weight gain despite eating what seems like a normal amount, your resting metabolic rate might be lower than average. This isn't a failure of willpower; it's a biological risk factor. To manage this, you likely need to be more consistent with physical activity and mindful of portion sizes than someone with a higher metabolic rate, as your body burns fewer calories at rest.