Food is the most fundamental input. Get this right and you've solved 60% of health. Get it wrong and no supplement, no protocol, no biohack will compensate. The good news: the basics aren't controversial. The science of what to eat is more settled than most other areas of health — it just gets buried under noise from fad diets, industry marketing, and the supplement aisle. This article is about food, not pills. For supplement-specific guidance, see Supplements.

The working definition of a good diet isn't a brand name or a macro ratio. It's a pattern: mostly whole foods, mostly plants, adequate protein, minimal added sugar and ultra-processed food, stable cooking fats. Every credible dietary researcher — from Walter Willett at Harvard to Tim Spector at ZOE — converges on some version of this. The disagreements are at the margins. The center is solid.

The Core Principles (What's Actually Settled)

These are the points of consensus across virtually all credible dietary research. If you did only these, you'd outperform ~90% of modern diets without tracking a single macro.

Principle	Why It Matters
Eat more plants than the average person	Fiber, polyphenols, and micronutrients come almost exclusively from plants. Diversity and quantity both matter.
Whole foods over processed	One of the most consistent findings in nutrition science. The more processing, the worse the health outcomes.
Adequate protein	1.2–2.0 g/kg bodyweight for most adults — higher than old RDAs, especially for older adults and anyone strength training.
Limit added sugar	Under 25g/day for women, 36g/day for men, ideally lower. See Sugar.
Limit ultra-processed foods	The NOVA Group 4 category is the single most consistent dietary villain in modern research.
Include fermented foods	For gut diversity and live cultures. See Gut Microbiome. Daily is better than weekly.
Variety matters	Diverse foods feed diverse microbes. ZOE/American Gut data: 30+ plant species per week predicts the healthiest microbiomes.
Cook with stable fats	Olive oil, butter, ghee, avocado oil. Not seed oils.

Everything downstream of these principles is refinement. Everything upstream is marketing.

Dietary Patterns That Have Strong Evidence

Foods to Prioritize

Not a ranking — a toolkit. Build meals from this list and the nutrition takes care of itself.

Food Category	Why It Matters	Target
Cruciferous Vegetables Broccoli, cauliflower, kale, Brussels sprouts, cabbage, arugula	Sulforaphane activates Nrf2, the master regulator of Phase II detoxification. Chopping + 40 min rest activates myrosinase. Broccoli sprouts have 10–100x the precursors of mature broccoli.	1–2 cups most days
Fatty Fish Salmon, sardines, mackerel, anchovies, herring	EPA/DHA, vitamin D, selenium, iodine, high-quality protein. Small, cold-water species are the sweet spot: high omega-3, low mercury. Canned sardines are cheap and shelf-stable.	2–3 servings/week
Berries Blueberries, blackberries, raspberries, strawberries	Anthocyanins — the strongest polyphenols in any fruit. Linked to vascular function, lower LDL oxidation, and neuroprotection. The MIND diet specifically identifies berries as protective against cognitive decline. Frozen is fine.	Daily if possible
Leafy Greens Spinach, arugula, swiss chard, collards, watercress	Folate, magnesium, vitamin K1, carotenoids, dietary nitrates. The Rush Memory & Aging Project found 1–2 servings/day correlated with cognitive age 11 years younger.	1–2 servings/day
Nuts and Seeds Almonds, walnuts, pumpkin seeds, chia, flax, hemp	Healthy fats, fiber, magnesium, vitamin E, lignans. PREDIMED specifically tested 30g/day mixed nuts and found significant CV benefit. Walnuts for ALA. Brazil nuts for selenium. Ground flax and chia for fiber and lignans.	1 oz (30g) daily
Legumes Beans, lentils, chickpeas, peas	Plant protein, high fiber, resistant starch, and remarkably stable blood sugar response. A consistent feature of "Blue Zone" populations. Soak or sprout for digestibility; pressure cooker is the single best purchase.	½–1 cup most days
Fermented Foods Yogurt, kefir, sauerkraut, kimchi, miso, natto, tempeh	Live cultures and postbiotic metabolites. A 2021 Stanford study showed a 10-week high-fermented-food intervention increased microbiome diversity and decreased 19 inflammatory markers. See gut-microbiome. Refrigerated, unpasteurized only — shelf-stable pickles are dead food.	A serving daily
Extra Virgin Olive Oil The defining fat of the Mediterranean diet	Monounsaturated fat and polyphenols (oleocanthal, hydroxytyrosol, oleuropein) with documented anti-inflammatory effects. High-polyphenol EVOO is surprisingly heat-stable — the polyphenols protect the oil from oxidation.	Primary cooking fat
Eggs Choline, lutein, zeaxanthin, complete protein	80% of Americans don't hit the choline adequate intake — eggs are the best source. Cholesterol panic was wrong: dietary cholesterol has minimal impact on blood cholesterol for most people. Pasture-raised have more omega-3, vitamin D, and carotenoids.	2–3/day is fine
Pasture-Raised Meat If you eat meat, quality matters	Omega-3:6 ratio ~1:1 vs 1:20 in feedlot beef. More CLA, vitamin K2, vitamin E, carotenoids. Differences biggest in fattier cuts (ground, marrow, organs). No routine antibiotics or growth hormones.	Prioritize for fatty cuts

Foods to Minimize or Avoid

Meal Composition Principles

Protein at Every Meal

Protein is the most satiating macronutrient, the most important for muscle preservation (especially over age 40), and a stable blood sugar anchor. Modern protein recommendations for healthy adults are 1.2–2.0 g/kg bodyweight, significantly higher than the 0.8 g/kg RDA (which is a minimum to prevent deficiency, not an optimum).

Target per meal: 30–40g of protein for most adults. Distribute evenly across 3 meals — muscle protein synthesis responds to distribution, not just total intake.

Good sources: Eggs, fish, poultry, grass-fed meat, Greek yogurt, cottage cheese, legumes, tofu, tempeh, edamame.

Fiber at Every Meal

Fiber feeds your microbiome (see gut-microbiome), stabilizes blood sugar, lowers LDL, improves satiety, and is one of the strongest single predictors of all-cause mortality in prospective studies. A 2019 Lancet meta-analysis of 185 prospective studies found that each 8g/day increase in fiber intake was associated with 5–27% reductions in mortality and disease risk.

The gap: Americans average ~15g/day. The target is 30–50g/day. This is one of the biggest practical wins available.

Good sources: Legumes, berries, avocado, chia, flax, psyllium, oats, artichokes, Brussels sprouts.

Don't Fear Fat (the Right Fats)

The low-fat era was a mistake. Replacing fat with refined carbs made everything worse. The fats to emphasize: olive oil, avocado, nuts, fatty fish, pasture-raised animal fats, butter, ghee, coconut oil. The fats to avoid: industrial seed oils, hydrogenated oils, trans fats. Saturated fat from whole foods — eggs, dairy, grass-fed meat — is not the villain the 1970s made it out to be. Recent meta-analyses have failed to link dietary saturated fat to cardiovascular disease in the absence of ultra-processing.

The Plate Method

Half the plate vegetables (especially non-starchy). A quarter protein. A quarter complex carbs or fruit. Simple, visual, works without tracking anything. The easiest rule to explain and the hardest rule to argue with.

Food Quality Questions

Question	When It Matters
Organic produce?	For the Dirty Dozen (strawberries, spinach, kale, grapes, peaches, pears, nectarines, apples, bell peppers, cherries, blueberries, green beans). Less critical for the Clean Fifteen (avocados, pineapples, onions, mushrooms, carrots, sweet potatoes, etc.). The case is about pesticide reduction, not nutrient density.
Grass-fed vs grain-fed meat?	Grass-fed has better omega-3:6 ratio, more CLA, more K2, more E, more carotenoids. Differences biggest in fattier cuts and organ meats — ground beef, marrow, tallow, liver. Less critical for lean cuts like sirloin and tenderloin.
Wild vs farmed fish?	Wild salmon: higher omega-3 per gram, lower contaminants, more astaxanthin. Farmed varies by farm quality — Norwegian and Scottish tend to be reasonable. Sardines, anchovies, and mackerel are essentially always wild.
Local & seasonal?	Less transit time = more retained nutrients. Seasonal variety naturally creates microbiome diversity. Farmers markets and CSAs are the easiest way in. Imperfect is fine.
Olive oil quality?	Fraud is rampant. Look for a harvest date (not "best by"), a dark bottle, origin from a single country (not "product of EU"), and third-party certifications (COOC, NAOOA). Polyphenol content is often listed on quality brands.

When You Eat — A Note on Timing

What you eat matters more than when, but timing isn't nothing. A few principles with decent evidence:

• Eating windows matter. Time-restricted eating has modest metabolic benefits — see fasting for the full picture.
• Earlier is generally better. Front-loading calories toward breakfast and lunch (rather than dinner) aligns with circadian metabolism. Insulin sensitivity is highest in the morning and declines through the day.
• Late-night eating is the worst. Eating within 2–3 hours of bed disrupts sleep, impairs glucose tolerance, and fights your circadian rhythm.
• Meal frequency is less important than meal composition. Whether you eat 2, 3, or 4 meals matters less than what's on the plate.

Practical Strategies

Honest Assessment