>I'm looking for a science-based source
Science is the last place I'd look if I wanted information about diet. Some of the worst, least reproducible stuff comes out of the nutritional science world. You can find studies for and against every diet and class of food.
The best place to start is tradition. What have you and your ancestors traditionally eaten? From there, make changes based on how you personally react to certain foods. From here, you can now very carefully look over some scientific studies to somewhat corroborate the effectiveness of your traditional diet.
But this is not nearly enough. As you do this, you have to be mindful of frequency; seasonality. Maybe your tribe kills a mammoth and you eat nothing but steaks, fat, high meat, and jerky for a month. Maybe your hunters come up short for the next month, so you live on foraged berries and rationed pemmican. In winter storms, the last thing you want to do is venture out into the crippling blizzard, so you subsist on stored tubers, or maybe you just starve for a week (you'll be fine). Maybe this kind of randomness is what your body is adapted for. Maybe this is your ideal diet.
Maybe Jews, Christians, and Muslims discovered the benefits of randomness in their diets and that's why they codified the practice of fasting in their books. And maybe there actually is some modern valid science to corroborate these ancient traditions.