What I Learned from 37 Nutrition Books
Three years ago, I read 37 widely varying books on nutrition, and I’ve distilled the overwhelming and often conflicting advice down to the most commonly agreed upon and scientifically validated core principles. While opinions differ at the edges, the fundamentals of what truly supports health, energy, and longevity are surprisingly well-aligned across credible sources.
Here’s what I learned, and it’s easy to incorporate into your life:
What to Eat
Focus on whole, unprocessed foods – build your diet around foods that exist in nature: vegetables, fruits, meats, fish, nuts, and seeds.
Make vegetables the star of your plate – vegetables (including salad) should be 50–75% of your food by volume, especially leafy greens and cruciferous veggies (broccoli, kale, cauliflower) to support gut health and reduce cancer risk. Include variety to diversify your gut microbiome, which science says has a substantial impact on your mood, immune function, energy, and overall well-being.
Eat plenty of fiber – chia, hemp, and flax seeds are all easy additions to smoothies and salads. (Most smoothies are unhealthy sugar bombs. If you want my Super Healthy Smoothie recipe, just email me at paul@behappiful.com.)
Get enough high-quality protein (at least 0.5g per lb of lean mass per day) mainly from fish, shellfish, eggs, poultry, and some plant sources. Include protein in every meal.
Eat healthy fats with every meal – olive oil, avocado, nuts, seeds, coconut/MCT oil, and fatty fish reduce inflammation and fuel the brain. Replace seed oils with olive or avocado oil.
Include fermented foods – unsweetened yogurt, sauerkraut, and kimchi help improve gut health and immunity.
Prioritize nutrient density, not calorie counting – the more vitamins, minerals, and phytonutrients per calorie, the better.
Choose the highest quality sources – organic produce, pasture-raised meats and dairy, and wild-caught fish whenever possible.
Stay hydrated and maintain electrolytes – drink 8 to 20 cups of water or herbal tea daily. If you’re active, use an electrolyte supplement. Water should be your main beverage. Personally, I keep a 40-ounce water bottle on my desk and drink and refill it 3-5 times a day.
What to Avoid
Cut out added sugar – in any form (honey, cane sugar, high-fructose corn syrup). Sugar drives obesity, metabolic disease, and even cancer.
Eliminate ultra-processed foods – eating just 10% more ultra-processed foods increases your risk of death by 10%. Avoid anything factory-made or packaged. Deli meats are out.
Skip fried foods – they’re loaded with unhealthy oils and compounds formed at high heat.
Ditch industrial seed oils – soybean, corn, canola, and sunflower oils are pro-inflammatory. Remove them from your kitchen.
Avoid artificial sweeteners – sucralose and aspartame disrupt gut bacteria and fuel cravings, acting much like sugar.
What to Limit
Greatly limit refined carbs – bread, pasta, rice (including brown rice), potatoes, pizza, bagels, pastries, crackers, chips, cereals, pancakes, and tortillas all spike blood sugar like sugar does. Your body can’t tell the difference between a bagel and a donut. And it’s best to eliminate all grains completely.
Natural sugars from fruit – stick to small portions. Favor berries; limit high-sugar fruits (bananas, pineapple, mango, grapes, cherries, apples). I used to eat an apple and a banana each day, but they have far too much sugar to be anything but an occasional treat.
Legumes – lentils and beans provide nutrients but are high in carbs; keep portions small.
Dairy – if you tolerate it, choose full-fat options and keep it limited. Plain Greek yogurt is best. Dairy can trigger inflammation in some people.
Charred meats – grilling, smoking, and deep-frying create carcinogens.
High-mercury fish – avoid swordfish and king mackerel; choose salmon, sardines, and light tuna instead.
Alcohol – even moderate drinking increases cancer risk (as well as disrupting your sleep and adding a lot of empty calories); if you drink, keep it rare and minimal (e.g., occasional red wine).
I don’t try to be in perfect compliance with these rules. When eating at a restaurant or at someone else’s house, I bend or break the rules. But by following these principles about 80% of the time, I’ve seen impressive health improvements while still eating great tasting food and enjoying the occasional treat.
Helpful Habits
Time-restricted eating – 12–16 hour overnight fasts improve insulin sensitivity and give your gut a break. I’ve been doing this for years, and I find it’s easy to eat dinner at 6 or 7 pm and then not eat until 11 am or 12 pm the next day. On the rare day that I feel a bit hungry in less time, I just eat my lunch earlier.
Align meals with daylight – eat earlier so that you finish meals at least 3 hours before bed. Your digestion and sleep will both improve.
Plan ahead – this helps you to choose healthy foods over convenience foods.
Clear out junk food – “Buy your discipline at the grocery store.” If it’s not in the house, you won’t eat it.
Practice mindful eating – follow hara hachi bu (“eat until 80% full”) to support longevity.
The Bottom Line
You don’t need the latest fad diet or expensive supplements. The basics are remarkably simple: eat real food, avoid sugar and processed junk, prioritize vegetables, quality proteins, and healthy fats, and develop habits that support consistency. And you don’t need perfection; just aim to follow these principles 80% of the time.
When I learned and started focusing on these fundamentals, I felt more energetic, had clearer thinking, lost 10 pounds, and improved my body composition and lab results, all without counting calories or feeling deprived. This stuff works.
Keep in mind that every body is different and you should consult with a medical professional before making any significant changes.
