Longevity V: Nutrition

Nutrition is the longevity topic everyone wants a clean answer to and almost nobody acts on. Most patients want to know which diet correlates with the longest lifespan. Then under 1% of them will make a sustainable change over the following year. The information isn't the bottleneck. It hasn't been for a long time.

So this piece is going to do two things. First, lay out what actually moves the needle. Second, name the reasons people don't follow through, because that's the more useful conversation.

Energy Balance Is Still the Whole Game

If you're underweight, you need to eat more. If you're overweight, you need to eat less. That's energy balance, and for most people there is no further practical takeaway from the topic. Body composition has a strong relationship with longevity, and total caloric intake is the lever that moves it.

The problem isn't that the equation is hard. The problem is that people have terrible insight into what they actually eat. We minimize the junk and overweight the wins. The fix is unglamorous: a 1–7 day food log, with three days being the sweet spot. Step one in any nutritional change is just figuring out what's currently going in.

The Diets All Point at the Same Thing

Mediterranean, DASH, Paleo, Blue Zones — they all gesture at the same underlying principle. Eat more whole foods. Avoid ultra-processed foods. Cooking is itself food processing, so I wouldn't get caught up in the details. The actionable version is: stop eating chemical foods. Chips, sodas, candy. That's the category that needs to shrink.

Liquid calories are their own problem, especially anything sweetened. Soda, sweetened coffee drinks, juice, and most "wellness" beverages are just sugar in a different uniform.

There's also a marketing trap worth naming. We've been trained to correlate certain food characteristics with health, and most of those correlations don't hold up. A gluten-free cookie is still a cookie. An alcohol-free beer is still extra liquid sugar calories. Read the label, not the front of the package.

The Added Sugar Rule

Most of the drugs that have actually extended lifespan in animal studies do something to glucose metabolism. That should tell you something. A reasonable general principle is to avoid added sugars whenever possible. The way you check is to look at the nutrition label — there's a line that says "added sugar." If the number is greater than zero, there's added sugar. Most processed foods will fail this test, which is precisely the point.

mTOR and the Case for Eating Less Often

The longevity literature spends a lot of time on mTOR — a cellular pathway that gets activated by protein (specifically leucine) and by insulin (which is spiked by sugar). The idea many longevity groups push is that minimizing mTOR stimulation over time supports lifespan.

The more nuanced read is that you don't want mTOR constantly activated. The practical translation is simple: don't graze all day. Time-restricted feeding — what most people call intermittent fasting — is the easiest application. You eat during a defined window and you don't eat outside it.

If you consume calories continuously throughout the day without significant activity to match, that's about the worst recipe you can write for metabolic health. Add late-night alcohol and short sleep on top, and you have the anti-recipe for both longevity and basic function.

Protein and Fiber: The Two Most People Miss

Protein becomes more important with age, not less. The target I work toward with patients is roughly 1 gram of protein per pound of lean body mass — a number we generate in clinic with body composition testing. The most common patient response is "that's a lot of protein." It is. It's a target to build toward, not a starting line.

Fiber is the other one. Most Americans are not consuming nearly enough, and the cardiovascular and metabolic costs are real. The good news is that the foods that solve both problems at once are the same — beans, legumes, and seeds. If you don't have time for that, chia seeds in a protein shake will get you partway there. Huel makes a meal-replacement shake that hits both targets, but I've had several patients tell me it tastes bad. I think it tastes like a protein shake, and a protein shake has never been on my list of memorable meals.

Goldilocks, Not Optimization

Nutrition is a Goldilocks problem. Not too much, not too little. The longevity-aligned default is "less food over time, not more." But that calibration shifts based on what you're doing. If you don't train, lean toward less. If you're chronically overtrained and underfed, lean toward more.

People are also genuinely different. Some respond better to higher fat, others to higher carbohydrate. Protein should stay relatively consistent and tied to lean mass. The macronutrient debate gets a lot more attention than it deserves because for most people it's not the limiting factor — total intake and food quality are.

Reading List

If you're going to read one book on nutrition, Michael Pollan's Food Rules is still the best. It's short, it's sane, and the core message — eat food, not too much, mostly plants — has aged better than almost anything in the field.

For a longevity-specific lens, Valter Longo's The Longevity Diet is worth reading, particularly his work on fasting-mimicking diets. The trifecta would be adding Mauro Di Pasquale's Anabolic Solution Diet for the body-composition angle. Combine the three and you've covered most of what's worth knowing.

Why People Don't Change

The information has been available for decades. The bottleneck isn't knowledge — it's insight, environment, and consistency. People don't actually know what they're eating, the foods designed to overconsume are everywhere, and most "diets" fail because they're acute interventions on a chronic problem.

The version that works is unglamorous. Track what you eat for a few days. Cut out the obvious junk. Build meals around protein and fiber. Stop drinking your calories. Don't eat all day long. Repeat for years. That's it. That's the whole thing.

3-Point Summary

• The diets that get longevity press all point at the same underlying advice: eat whole foods, avoid ultra-processed foods, and eat less over time. The branding matters less than the behavior.

• Most patients have poor insight into what they actually eat. A 1–3 day food log fixes more nutritional problems than any specific diet plan.

• Protein and fiber are the two macronutrients most adults under-consume. Both come bundled in beans, legumes, and seeds — which is why those foods anchor every longevity-associated diet.

3 Practical Takeaways

• Run a 3-day food log. Write down everything you eat and drink, no editing. Don't try to fix anything yet — just see what's actually happening. Most people are surprised, which is the entire point.

• Read the "added sugar" line on every label. If the number is greater than zero, treat that food as an occasional item, not a staple. This single rule eliminates most of the worst foods in the American diet without requiring you to memorize anything.

• Build meals around protein and fiber. Aim for roughly 1g protein per pound of lean body mass and a meaningful serving of beans, legumes, or seeds at most meals. Solve both problems with the same fork.