>>12226970Because you are eating a nutrient poor diet.
Most of the B-vitamins have antioxidant properties, so if you eat a food that has a higher ratio of calories and inflammation to antioxidants then your body cannot burn the calories because to do so would have severe inflammation which would kill you.
Healthy whole foods have a balanced ratio of calories to vitamins/minerals/anitoxidants. Things like refined wheat with refined oil with factory farmed chicken will have low nutrition status by high calories.
