Also, watch out for orange juice or tums! Orange juice or anything really acidic do not mix with adhd meds, and if taken simultaneously or close together, can negate the effect. Supposedly this is an "urban legend", but neither amphetamines nor ritalin (a quasi-amphetamine) work well in an acidic environment.
Tums make your stomach more alkaline, and make the medications stronger....I didn't know that, or at least not consciously....til I did it....I hadn't "felt" my medication for years, and it was like "OH! Hello!" I could definitely feel it, really feel it, and that's not a good thing, because it IS a pleasurable sensation, and you don't want to rely on that or crave it. That's not the purpose of it.
So just be careful with what you eat and drink right when you take it, an empty stomach is best, but it's not like you have to obsess about it, most things will affect it very little, and it's not like it will kill you or make you sick. Just be aware that foods can have a marginal effect on it, as well as other medicines. And if you take it with, say, Red Bull or something, it may make you either jittery or tired.