In my postdoc, I had identified there were vitamin D response elements in genes that convert tryptophan into serotonin in the brain ... If you don't have enough vitamin D, then you can't convert the amino acid tryptophan into serotonin in the brain. Serotonin is important for mood. It's important for executive function. It's important for impulse control. So people that don't have enough serotonin, they have a lot of problems with long-term planning and controlling their impulses.

There are studies where healthy young men drink equivalent of, you know, 12 oz. soda, and their inflammatory biomarkers increased by 100% within, like, 24 hours. And that is substantial, because inflammation ... is not isolated to the immune system. Immune cells are creating a lot of these inflammatory cytokines, but those are then signaling to our brain, and they play a role in depression; they play a role in what people call brain fog.

So it regulates 5% of the protein-encoding human genome. So we could spend the next hour talking about all the genes that vitamin D regulates; it's that many; it's over 1,000 genes—everything from brain function to immune function. It plays a role in, again, bone health, muscle function. Pretty much every every organ that you can think of vitamin D is doing something in that that organ. It's so important.

You can look at it through the lens of, okay, what should I avoid and not eat, which, I get that, but I also think if you try to look through the lens of what do I need to fuel my body, then you end up avoiding the refined carbohydrates because there's no vitamins and minerals or anything, proteins; you're not getting the nutrients that you need.

There's no real nutrition in these processed foods that are calorically dense and micronutrient poor. You're just adding on calories that are going to cause inflammation.

I think a whole foods diet, something more like a paleo diet, really is one of the best ways to eat. That's the way I try to eat. And really what it is is you're getting all the beneficial micronutrients from greens, and you're getting polyphenols and phytochemicals from fruits, and you're getting the protein from the meats, and you're avoiding the refined processing packaged foods.

So avoiding the processed foods, I think, is a great way to eat, you know, but something closer to a Mediterranean diet, whole foods. diet, paleo diet. You just can't go wrong, really.

I think now a lot of research coming out from the last decade or so has shown that the RDA for protein intake in the US, which is currently 0.8 grams per kilogram body weight, is too low.

70% of the US population has insufficient vitamin D.

There's nothing comparable to what exercise can do, especially vigorous intensity exercise in particular.

I think a good rule of thumb is stop eating three hours before bed.