Multivitamin pills

The most I have seen multi-vitamins be is 15 calories/pill. 15 calories can be burnt by:

• sitting still for 10 minutes
• Drinking a cup of hot black tea (heat costs energy to dissipate)
• walking for 2 minutes

Since calories-in-calories-out is tied to fundamental laws of the universe they certainly won't make you fat on their own (unless you have another kind of syrup or pill I'm not familiar with that is very high in calories!) The question however, could be posed. Do multivitamins change the efficiency at which our bodies absorb nutrients?

This... isn't well studied, but the worst-to-best metabolism differences differ from ~200 calories a day based on a 2000 calorie diet. I don't see a good reason why this should be but I suppose it can't be discounted. I really don't think multivitamins will do you any good if you already have an even somewhat reasonable diet. The best study available on the topic suggests that those who take multivitamins are more likely to become sick and die (by a VERY small amount!).

I'd try to consume everything you normally would in a time period (say a month) without a multivitamin and then see a doctor to determine if you are suffering from any serious deficiencies. Any deficiencies can then be taken care of by more specific supplementation.