(WellandGoodNYC.com) -- We spend a lot of time cooking quinoa, throwing back green juice, and just generally trying to optimize our diet. But even the seemingly healthiest eating habits may not deliver all the nutrients you need. Why?

“Our poor food supply,” says nutritionist (and Brooklyn Bridge Boot Camp founder) Ariane Hundt, citing depleted soil, pesticides, and harvesting foods early to ship them. Not to mention lifestyle issues like desk jobs, which steal your vitamin D.

So is your multivitamin enough to cover these losses? To determine your ideal daily dose, we asked a handful of experts for there rules on taking supplements.

Rule 1: Get It From Food First. This may be obvious, but it’s worth repeating. “Supplements are meant to do just that—supplement—your diet, and in no way replace eating healthy foods,” says Keri Glassman, celeb nutritionist and founder of Nutritious Life. “Our bodies are designed to reap all of our nutrients from the food we eat from a healthy varied diet.”

All of the experts we asked agreed. Double cheeseburgers with a perfect regimen of pills and powders just won’t cut it.

Rule 2: Make Sure You’re Absorbing Nutrients. Even if you’re eating well and taking supplements, you may not be taking in as many nutrients as you’d think.

Drinking coffee, for example, inhibits absorption of iron and calcium, and vitamin D absorption depends on your calcium levels. You should take supplements with a meal for maximum absorption, says Ariane Hundt.