Paleo diet

For 2.6 million years, our Paleolithic ancestors ate a diet high in wild animal protein and fat, with some gathered plant foods. There was no wheat, rice, pasta, flour, potatoes, or refined sugar. Agriculture was invented only 11,000 years ago. Dairy foods such as milk and cheese were invented only 6,000 years ago.

In modern times, isolated tribes of hunter-gatherers still eat a Paleo diet. As a result, their Body Mass Index (BMI) is 19–20 (someone who is 5’8 and 131 pounds has a BMI of 20). No one is overweight or obese. And almost no one has heart disease or diabetes.

In contrast, the United States is suffering from an obesity epidemic. About 30% of adults are overweight (BMI of 25–30). Another 40% are obese (BMI >30).

For example, filmmaker Morgan Spurlock ate nothing but McDonald’s for 30 days in the documentary Super Size Me. He gained 25 pounds and suffered mood swings, sexual dysfunction, and liver damage.

Overall, the human body has evolved over millions of years to eat protein, fat, fruits, and vegetables.

I eat like a caveman.

-Jennifer Lawrence

Back to basics

Eating Paleo improves health quickly. For example, professor Kerin O’Dea convinced 10 Australian Aborigines to leave their modern lives and live as hunter-gatherers for 7 weeks. The Aborigines were in their 50s, overweight, and diabetic.

Once in the Outback, they ate kangaroo, fish, yams, birds, and crocodiles. They were only eating 1,200 calories per day, but didn’t feel hungry because of the high protein and fiber.

Results were remarkable. The Aborigines lost an average of 18 pounds, and their diabetes reversed to near-normal levels of blood glucose, insulin, and triglycerides.

Primitive societies are largely free of cardiovascular disease, cancer, dental cavities, economic theories, lounge music, and other modern ailments.

-Nassim Taleb

Importance of a Paleo diet

Here are jaw-dropping benefits:


  • Lose weight naturally and maintain an optimal BMI of 19–22

      • Muscular athletes may have a higher BMI

      • e.g., tennis star Roger Federer has a BMI of 24.8

  • Almost completely prevent heart disease, stroke, and diabetes

  • 10–15% lower risk of cancer

  • Live 2–4 years longer or more


  • 40% better cognition for older adults


  • 35% better mood

  • 20% more energy


  • Women can lose weight and go from 5 to 8 on a 10-point scale

Think about it: Heart disease and diabetes, which account for more deaths in the U.S. and worldwide than everything else combined, are completely preventable by making comprehensive lifestyle changes. Without drugs or surgery.

-Dean Ornish

How to eat Paleo

Eat a mix of protein, fat, fruits, and vegetables

  • Eat until you’re 80% full

  • If you’re hungry between meals, eat more protein because you’ll feel full longer

For protein, eat chicken, fish, shellfish, eggs, nuts, legumes, pasture-fed red meat, and wild meat

  • Limit grain-fed beef and pork

  • Limit cheese and yogurt

  • Limit processed meat such as bacon and sausage

For fat, eat omega-3 fats and unsaturated fats

  • e.g., wild and farmed salmon is high in omega-3 fats

  • e.g., nuts and olive oil are high in unsaturated fats

  • Limit saturated fats such as butter and cream

  • Avoid trans fats completely

For fruits, eat raw, whole fruits

  • Avoid fruit juice

  • Avoid processed fruit

For vegetables, eat non-starchy vegetables

  • Adding oil to salad is required to absorb antioxidants

  • Limit starchy vegetables such as potatoes

  • Avoid processed vegetables

For beverages, drink water or unsweetened tea or coffee

  • Limit 2% and whole milk

  • Avoid skim and 1% milk because there’s not enough fat to slow absorption of lactose sugar

Avoid foods containing simple carbohydrates

  • e.g., bread, pasta, rice, chips, cookies, cake

Avoid foods containing sugar

  • e.g., soft drinks, candy

Don’t eat anything your great grandmother wouldn’t recognize as food.

-Michael Pollan

Salad dressing

At Iowa State University, researchers prepared salads with spinach, romaine lettuce, cherry tomatoes, and carrots. They added fat-free, reduced-fat, or full-fat salad dressings. Volunteers ate the salads, then had their blood tested for antioxidants such as beta-carotene and lycopene.

With fat-free dressing, there was almost zero absorption of antioxidants. In contrast, there was excellent absorption with monounsaturated fats such as olive oil or canola oil.

The promotion of low-fat diets was a 40-year fad, with disastrous outcomes, conceived of, authorized, and policed by nutritionists.

-Ian Leslie


In Tanzania, Bantu villagers live on the shores of Lake Nyasa and eat lots of fish. In nearby hills, other villagers eat a vegetarian diet. In a study of both groups, researchers found that 16% of vegetarians had high blood pressure versus 3% of fish-eaters. Also, fish-eaters had 14% lower cholesterol and 3X higher levels of healthy omega-3 fats.

It’s not just Tanzania. A study of 229 hunter-gatherer societies found that 73% ate more than half of their calories from hunted or fished animal foods. None ate mostly gathered plant foods.

The problem is most vegetarian diets are low in protein and omega‐3 fats. Also, some vegetarians eat simple carbohydrates such as rice, bread, pasta, and sugar. Your body has evolved over millions of years to eat animal protein—it’s a mistake to cut it out of your diet.

Omega-3 fats

In plants, omega-3 fats function as antioxidants that protect cell membranes. When animals eat plants, omega-3 fats accumulate in their tissues. When you eat animals, the omega-3 fats become building blocks for your body, especially the brain. They also serve as antioxidants and reduce inflammation.

Cows that eat grass have meat that is high in omega-3 fats, whereas cows that eat grain do not. This is why grass-fed, free-range, and wild protein is better for your health.

You are what what you eat eats.

-Michael Pollan


Fruits and vegetables naturally contain vitamins and antioxidants. For example, blueberries, tomatoes, and spinach are loaded with antioxidants that prevent browning from oxygen in air.

If you eat Paleo, your diet should contain more than enough vitamins and antioxidants. That being said, consider taking 800 IU or more of vitamin D per day to boost your immune system against COVID-19, especially in northern climates.

If you’re planning to have a baby, take prenatal vitamins to prevent neural tube defects, cleft palate, and other abnormalities. And if you’re older, take 800 IU of vitamin D and 1,200 mg of calcium per day to prevent fractures.

Let food be thy medicine and medicine be thy food.


How to start today

Here is a 3-week plan:

    • Week 1: eat Paleo every breakfast

        • Put a cue in a highly-visible place, like a bag of oatmeal on your kitchen counter

    • Week 2: add every lunch

        • Put a highly-visible cue in your fridge, like a container of baby spinach

    • Week 3: add every dinner

        • Once a week, make it a habit to buy fruits and vegetables

        • Put away non-Paleo food so it’s less visible, like in a cupboard

Cheat foods

  • If you eat simple carbohydrates, eat them after a meal of protein and vegetables because this lowers the blood sugar spike by 50%

  • Your health should be fine if you eat non-Paleo meals 10–20% of the time

People have got to learn: if they don’t have cookies in the cookie jar, they can’t eat cookies.

-Suze Orman

Example meals


  • Oatmeal + peanut butter + blueberries + banana

  • Scrambled eggs + avocado + tomatoes

Lunch and Dinner

  • Roast chicken + salad

  • Baked salmon + stir-fried vegetables

  • Chili with kidney beans and ground beef

Snacks and Dessert

  • Nuts

  • Fruits

The 3 most harmful addictions are heroin, carbohydrates, and a monthly salary.

-Nassim Taleb


Carrera-Bastos P et al. (2011). The western diet and lifestyle and diseases of civilization. Res Rep Clin Cardiol. 2: 15–35.

  • In hunter-gatherer populations, the following diseases are rare or virtually absent: coronary heart disease, obesity, hypertension, type 2 diabetes, epithelial cell cancers, autoimmune disease, and osteoporosis

Gurven M, Kaplan H. (2007). Longevity among hunter-gatherers: a cross-cultural examination. Popul Dev Rev. 33(2): 321–365.

  • A study of 17 modern-day hunter-gatherer populations with 30,849 individuals and 3,328 deaths found that average life span was 72 years

  • Top causes of death were infectious illnesses (70%), violence and accidents (20%), and degenerative diseases (9%)

Cordain L et al. (2005). Origins and evolution of the Western diet: Health implications for the 21st century. Am J Clin Nutr. 81(2): 341–354.

  • Dairy products, cereals, refined sugars, refined vegetable oils, and alcohol comprise 72.1% of total daily energy consumed by modern Americans, whereas these foods were almost non-existent in pre-agricultural diets

  • Widespread consumption of highly-refined grain flours occurred in the past 150 to 200 years

  • Fat storage cells of wild animals contain >50% of fat in the form of saturated fatty acids (SFAs), whereas muscle and organ tissues contain mainly polyunsaturated fatty acids (PUFAs) and monounsaturated fatty acids (MUFAs)

  • Wild animals have low fat stores during most of the year, which means PUFAs and MUFAs usually comprise most of total carcass fat

  • Before 1850, virtually all U.S. cattle were free-range or pasture-fed, and were typically slaughtered at 4–5 years of age

  • In the 1950s, modern feedlots enabled an obese (30% body fat) 545-kg steer to be brought to slaughter in 14 months

  • In the United States, 99% of beef is produced from grain-fed, feedlot cattle, whereas almost no beef was produced this way as recently as 200 years ago

  • Beef with high SFAs, low omega-3 fats, and high omega-6 fats are a recent component of human diets

  • In the modern American diet, the ratio of omega-6 to omega-3 PUFAs has risen to 10:1, whereas the ratio in hunter-gatherer diets was 2:1 to 3:1

  • Compared to whole grains, fresh fruit typically contains 2X the amount of fiber, and non-starchy vegetables contain almost 8X

Cordain L et al. (2000). Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets. Am J Clin Nutr. 71(3): 682–692.

  • Out of 229 hunter-gatherer societies, 73% derived >50% of subsistence from hunted or fished animal foods

  • No hunter-gatherer society was entirely or largely dependent on gathered plant foods, whereas 20% were highly or solely dependent (86–100%) on fished or hunted animal foods

  • When early American explorers ate excessive lean meat from wild animals, they experienced “rabbit starvation”, with symptoms including nausea, diarrhea, and even death

  • Muscle tissues of wild, hoofed animals typically contain 2–3% fat by weight

  • Therefore, most hunter-gatherer societies probably avoided rabbit starvation by eating more fat from animal foods

  • Our hunter-gatherer ancestors probably ate a diet comprising 19–35% protein, 22–40% carbohydrate, and 28–58% fat

Jacobi R, Current A, Stringer C. (2000). Gough’s Cave and Sun Hole Cave human stable isotope values indicate a high animal protein diet in the British Upper Palaeolithic. J Archaeol Sci. 27(1): 1–3.

  • Paleolithic diets were high in animal protein as indicated by isotope ratios in bone collagen from human skeletons

Kirchengast S. (1998). Weight status of adult !Kung San and Kavango people from northern Namibia. Ann Hum Biol. 25(6): 541–551.

  • !Kung San hunter-gatherers have an average BMI of 19.1 for women and 19.4 for men

Pontzer H et al. (2012). Hunter-gatherer energetics and human obesity. PLoS One. 7(7): e40503.

  • Hazda are modern-day hunter-gatherers who have an average BMI of 20 vs. 27 for Western populations

  • Average daily energy expenditure from physical activity is the same for Hazda and Westerners after controlling for body size

  • Therefore, the difference in BMI is likely due to the hunter-gatherer diet vs. Western diet

Rudman D et al. (1973). Maximal rates of excretion and synthesis of urea in normal and cirrhotic subjects. J Clin Invest. 52(9): 2241–2249.

  • Human protein limit is 200–300 g per day

Osterdahl M et al. (2008). Effects of a short-term intervention with a paleolithic diet in healthy volunteers. Eur J Clin Nutr. 62(5): 682–685.

  • 20 medical students (average BMI: 22.2; blood pressure: 110/65) were placed on a Paleo diet (fruits, vegetables, lean protein, fish) for 3 weeks

  • BMI decreased to 21.4 and blood pressure decreased to 104/61

Aune D et al. (2016). BMI and all cause mortality: systematic review and non-linear dose-response meta-analysis of 230 cohort studies with 3.74 million deaths among 30.3 million participants. BMJ. 353: i2156.

  • A meta-analysis of 230 cohort studies with 30,233,329 participants found that a BMI of 20–22 was associated with lowest all-cause mortality

Whitlock G et al. (2009). Body-mass index and cause-specific mortality in 900 000 adults: collaborative analyses of 57 prospective studies. Lancet. 373(9669): 1083–1096.

  • An analysis of 57 prospective studies with 894,576 participants found that a BMI of 30–35 reduced lifespan by 2–4 years

  • BMI of 40–45 reduced lifespan by 8–10 years

Fryar CD, Carroll MD, Afful J. (2020). Prevalence of overweight, obesity, and severe obesity among adults aged 20 and over: United States, 1960–1962 through 2017–2018. NCHS Health E-Stats.

  • A study of 5,120 Americans found that 31.1% were overweight and another 42.5% were obese

Back to basics

O’Dea K. (1984). Marked improvement in carbohydrate and lipid metabolism in diabetic Australian aborigines after temporary reversion to traditional lifestyle. Diabetes. 33(6): 596–603.

  • 10 diabetic, overweight Aborigines lived as traditional hunter-gatherers for 7 weeks

  • Animal food was 64% of total energy intake, and the proportions were: kangaroo (36%), yams (28%), fish (19%), birds and crocodiles (17%)

  • Average energy intake was 1,200 kcal/day and weight loss was 8 kg

  • Fasting blood glucose fell from 11.6 to 6.6 mM; fasting plasma insulin fell from 23 to 12 mU/L; and fasting plasma triglycerides fell from 4.0 to 1.2 mM

Lifestyle change, diabetes and related conditions in Australian Aboriginals: Professor Kerin O’Dea. (2019, May 10). Education Nutrition.

  • Despite eating only 1,200 calories/day, high protein and fiber aided satiety


Valls-Pedret C et al. (2015). Mediterranean diet and age-related cognitive decline: A randomized clinical trial. JAMA Intern Med. 175(7): 1094–1103.

  • A 6-year randomized trial of 447 participants with an average age of 67 found that eating a Mediterranean diet plus olive oil improved global cognition by 5% vs. a decrease of 38% for the control diet


Breymeyer KL et al. (2016). Subjective mood and energy levels of healthy weight and overweight/obese healthy adults on high-and low-glycemic load experimental diets. Appetite. 107: 253–259.

  • A randomized cross-over-controlled study with 82 participants found that eating high glycemic-load diets for 4 weeks resulted in higher scores for total mood disturbance (55%), depressive symptoms (38%), and fatigue/inertia (26%)

Mujcic R, Oswald A. (2016). Evolution of well-being and happiness after increases in consumption of fruit and vegetables. Am J Public Health. 106(8): 1504–1510.

  • A 6-year longitudinal study of 12,385 participants found that eating 8 portions of fruits and vegetables per day increased life-satisfaction by 0.24 points over 24 months (equivalent to psychological gain from moving from unemployment to employment)


Long G et al. (2020). Comparison of dietary macronutrient patterns of 14 popular named dietary programmes for weight and cardiovascular risk factor reduction in adults: systematic review and network meta-analysis of randomised trials. BMJ. 369: m696.

  • A meta-analysis of 121 trials with 21,942 participants found that low-carbohydrate and low-fat diets resulted in similar weight loss at 6 months (4.63 vs. 4.37 kg, respectively)

Mancini JG et al. (2016). Systematic review of the Mediterranean Diet for long-term weight loss. Am J Med. 129(4): 407–415.

  • A meta-analysis of 5 studies with 998 participants found that a Mediterranean diet resulted in greater weight loss than a low-fat diet after 12 months (-4.1 to -10.1 kg vs. +2.9 to -5.0 kg)

Mozaffarian D et al. (2011). Changes in diet and lifestyle and long-term weight gain in women and men. N Engl J Med. 364(25): 2392–2404.

  • A 20-year prospective study of 120,877 individuals who were free of chronic diseases and not obese at baseline found that 4-year weight gain was most strongly associated with eating potato chips (1.69 lb), potatoes (1.28 lb), sugar-sweetened beverages (1.00 lb), unprocessed red meats (0.95 lb), and processed meats (0.93 lb)

  • There was an inverse association with eating yogurt (-0.82 lb), fruits (-0.49 lb), nuts (-0.57 lb), whole grains (-0.37 lb), and vegetables (-0.22 lb)

  • Other lifestyle factors included exercise (-1.76 lb), alcohol use (0.41 lb per drink per day), and watching television (0.31 lb per hour per day)

Swami V, Tovée MJ. (2005). Female physical attractiveness in Britain and Malaysia: a cross-cultural study. Body Image. 2(2): 115–128.

  • 682 male and female participants from Britain and Malaysia rated images of 50 real women, and the most attractive BMI was 21

  • On a 6-point scale, women with a BMI of 21 were rated about 5 vs. 3 for a BMI of 30

Crossley KL, Cornelissen PL, Tovée MJ. (2012). What is an attractive body? Using an interactive 3D program to create the ideal body for you and your partner. PLoS One. 7(11): e50601.

  • 40 men and 40 women used 3D interactive software to set size and shape of their ideal partner

  • The most attractive female BMI was 19, and the most attractive male BMI was 24.5

Swami V, Tovée MJ. (2005). Male physical attractiveness in Britain and Malaysia: A cross-cultural study. Body Image. 2(4): 383–393.

  • 95 female participants from Britain and Malaysia rated images of 50 real men, and the most attractive BMI was 21

  • On an 8-point scale, men with a BMI of 21 were rated about 5.5 vs. 3 for a BMI of 27

Tovée MJ et al. (1998). Optimum body-mass index and maximum sexual attractiveness. Lancet. 352(9127): 548.

  • 40 male students rated images of 50 real women, and the most attractive BMI was 19–20

Stephen ID et al. (2009). Facial skin coloration affects perceived health of human faces. Int J Primatol. 30(6): 845–857.

  • 51 individuals were photographed and rated by 32 other participants

  • Eating fruits and vegetables increased carotenoid skin concentrations and contributed to a healthy glow

How to eat Paleo

Fukkoshi Y, Akamatsu R, Shimpo M. (2015). The relationship of eating until 80% full with types and energy values of food consumed. Eat Behav. 17: 153–156.

  • A study of 330 participants found that men who always ate until they were only 80% full consumed 18% fewer calories and 50% more vegetable dishes

Dhillon J et al. (2016). The effects of increased protein intake on fullness: A meta-analysis and its limitations. J Acad Nutr Diet. 116(6): 968–983.

  • A meta-analysis of 5 studies found that eating more protein increased ratings of fullness

Chicken, Red meat

Wang X et al. (2015). Red and processed meat consumption and mortality: dose-response meta-analysis of prospective cohort studies. Public Health Nutr. 19(5): 893–905.

  • A meta-analysis of 9 studies with 1.1 million participants found that eating 1 serving/day of processed meat increased risks of cardiovascular death (15%) and cancer death (8%)

  • Eating 1 serving/day of unprocessed red meat increased risks of cardiovascular death (19%) and cancer death (12%)

Abete I et al. (2014). Association between total, processed, red and white meat consumption and all-cause, CVD and IHD mortality: a meta-analysis of cohort studies. Br J Nutr. 112(5): 762–775.

  • A meta-analysis of 13 cohort studies with 1,674,272 individuals found that eating red meat increased risk of cardiac death by 16% vs. no increased risk for white meat

  • Eating processed meat increased risk by 18%

Pan A et al. (2012). Red meat consumption and mortality: results from 2 prospective cohort studies. Arch Intern Med. 172(7): 555–563.

  • A prospective study of 37,698 men and 83,644 women estimated that substituting 1 serving/day of red meat with fish/chicken/nuts/legumes/low-fat dairy/whole grains would lower risk of death by 7–19%

Pan A et al. (2011). Red meat consumption and risk of type 2 diabetes: 3 cohorts of US adults and an updated meta-analysis. Am J Clin Nutr. 94(4): 1088–1096.

  • A meta-analysis of 442,101 men and women found that eating 100 g per day of unprocessed red meat increased risk of type 2 diabetes by 19%

  • Eating 50 g per day of processed red meat increased risk by 51%

Daley CA et al. (2010). A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef. Nutr J. 9: 10.

  • Average ratio of omega-6 to omega-3 in grass-fed beef is 1.53:1 vs. 7.65:1 for grain-fed beef

  • Beta-carotene levels are 7X higher in grass-fed vs. grain-fed beef

Bernstein AM et al. (2010). Major dietary protein sources and risk of coronary heart disease in women. Circulation. 122(9): 876–883.

  • A prospective study of 84,136 women over 26 years found that risk of cardiovascular death was decreased by eating 1 serving/day of nuts (30% lower), fish (24% lower), or chicken (19% lower) vs. red meat or high-fat dairy


Raji CA et al. (2014). Regular fish consumption and age-related brain gray matter loss. Am J Prev Med. 47(4): 444–451.

  • A study of 260 participants over 10 years found that eating fish at least once per week increased size of brain regions responsible for memory and cognition by 4.3–14%

Mozaffarian D, Rimm EB. (2006). Fish intake, contaminants, and human health: evaluating the risks and the benefits. JAMA. 296(15): 1885–1899.

  • Across 16 prospective and randomized trials, eating fish high in omega-3 once or twice a week reduced risk of cardiovascular death by 36% and total mortality by 17%

Foran JA et al. (2005). Quantitative analysis of the benefits and risks of consuming farmed and wild salmon. J Nutr. 135(11): 2639–2643.

  • Wild salmon has an omega-3 to omega-6 ratio of 10:1 vs. 4:1 for farmed salmon i.e., 2.5X more omega-3 in wild salmon

Kris-Etherton PM et al. (2002). Fish consumption, fish oil, omega-3 fatty acids, and cardiovascular disease. Circulation. 106(21): 2747–2757.

  • Randomized trials showed that eating fish lowered risk of heart disease by 20–30%


Drouin-Chartier J et al. (2020). Egg consumption and risk of cardiovascular disease: three large prospective US cohort studies, systematic review, and updated meta-analysis. BMJ. 368: m513.

  • A 32-year prospective study of 14,806 participants and a meta-analysis of 27 studies found that eating at least 1 egg per day did not increase risk of heart disease

Blesso CN et al. (2013). Whole egg consumption improves lipoprotein profiles and insulin sensitivity to a greater extent than yolk-free egg substitute in individuals with metabolic syndrome. Metabolism. 62(3): 400–410.

  • A randomized, single-blind, 12-week study of 37 participants found that eating 3 whole eggs per day vs. yolk-free egg substitutes did not change total cholesterol, and improved atherosclerosis lipid profiles by 13.5% vs. 9.5%

Valentine N et al. (2010). Daily egg consumption in hyperlipidemic adults - Effects on endothelial function and cardiovascular risk. Nutr J. 9:28.

  • A randomized placebo-controlled cross-over trial of 40 participants found that eating eggs every day for 6 weeks did not increase total cholesterol


Aune D et al. (2016). Nut consumption and risk of cardiovascular disease, total cancer, all-cause and cause-specific mortality: a systematic review and dose-response meta-analysis of prospective studies. BMC Med. 14(1): 207.

  • A meta-analysis of 20 studies found that eating 28 g of nuts per day decreased risks of diabetes (39%), neurodegenerative disease (35%), coronary artery disease (29%), all-cause mortality (22%), and total cancer (15%)

Luu HN et al. (2015). Prospective evaluation of the association of nut/peanut consumption with total and cause-specific mortality. JAMA Intern Med. 175(5): 755–766.

  • A cohort analysis of over 200,000 participants found that eating nuts lowered risk of death by about 20%, comparing highest vs. lowest quintiles

  • Risk of ischemic heart disease was lowered by about 40%


Clifton PM, Keogh JB. (2017). A systematic review of the effect of dietary saturated and polyunsaturated fat on heart disease. Nutr Metab Cardiovasc Dis. 27(12): 1060–1080.

  • A review of systematic reviews and meta-analyses from 2010 to 2017 found that high intake of saturated fats and trans fats increased risk of death by 8–13%

  • Replacement of saturated fats with monounsaturated fats or polyunsaturated fats reduced risk of death by 11% and 19%, respectively

Pimpin L et al. (2016). Is butter back? A systematic review and meta-analysis of butter consumption and risk of cardiovascular disease, diabetes, and total mortality. PLoS One. 11(6): e0158118.

  • A meta-analysis of 9 studies with 636,151 individuals found that eating butter did not increase risks of death, heart disease, stroke, or diabetes

de Souza RJ et al. (2015). Intake of saturated and trans unsaturated fatty acids and risk of all cause mortality, cardiovascular disease, and type 2 diabetes: systematic review and meta-analysis of observational studies. BMJ. 351: h3978.

  • A meta-analysis of 41 studies found that eating saturated fat did not increase risks of all-cause mortality, cardiovascular mortality, coronary artery disease, stroke, or type 2 diabetes

  • Trans fat increased risks of all-cause mortality (34%), cardiovascular mortality (28%), and coronary heart disease (21%)

Schwingshackl L, Hoffmann G. (2014). Monounsaturated fatty acids, olive oil and health status: a systematic review and meta-analysis of cohort studies. Lipids Health Dis. 13: 154.

  • A meta-analysis of 32 cohort studies with 841,211 individuals found that eating olive oil reduced risks of stroke (40%), cardiovascular mortality (30%), all-cause mortality (23%), and coronary artery disease (20%)

  • Monounsaturated fats of mixed animal and vegetable sources did not reduce risk

O’Sullivan TA et al. (2013). Food sources of saturated fat and the association with mortality: A meta-analysis. Am J Public Health. 103(9): e31–e42.

  • A meta-analysis of 26 studies found that high intakes of milk, cheese, yogurt, and butter did not increase risk of death

Mozaffarian D et al. (2006). Trans fatty acids and cardiovascular disease. N Engl J Med. 354(15): 1601–1613.

  • Trans fats increase heart disease

Fruits, Vegetables

Aune D et al. (2017). Fruit and vegetable intake and the risk of cardiovascular disease, total cancer and all-cause mortality—a systematic review and dose response meta-analysis of prospective studies. Int J Epidemiol. 46(3): 1029–1056.

  • A meta-analysis of 95 cohort studies found that eating 800 g per day of fruits and vegetables decreased risks of stroke (33%), all-cause mortality (31%), cardiovascular disease (28%), coronary heart disease (24%), and total cancer (14%)

Song M et al. (2016). Association of animal and plant protein intake with all-cause and cause-specific mortality. JAMA Intern Med. 176(10): 1453–1463.

  • A prospective cohort study of 131,342 individuals found that eating plant protein decreased risk of death by 10% for each 3% energy increment that replaced animal protein

Wang X et al. (2014). Fruit and vegetable consumption and mortality from all causes, cardiovascular disease, and cancer: systematic review and dose-response meta-analysis of prospective cohort studies. BMJ. 349: g4490.

  • A meta-analysis of 16 prospective cohort studies with 833,234 individuals found that each 1 serving/day of fruits and vegetables lowered risk of death by 5%

  • There was a threshold around 5 servings/day, after which risk of death was not further reduced

Oyebode O et al. (2014). Fruit and vegetable consumption and all-cause, cancer and CVD mortality: analysis of Health Survey for England data. J Epidemiol Community Health. 68(9): 856–862.

  • A 12-year prospective study of 65,226 individuals found that eating 7+ portions of fruits and vegetables per day decreased risk of death by 33%

  • Eating 2–3 portions of vegetables per day decreased risk of death by 19% vs. 10% with fruits

Muraki I et al. (2013). Fruit consumption and risk of type 2 diabetes: results from three prospective longitudinal cohort studies. BMJ. 347: f5001.

  • A prospective, longitudinal cohort study of over 150,000 individuals found that eating 3 servings/week of blueberries decreased risk of diabetes by 26%

  • Risk of diabetes was also decreased by 12% for grapes and raisins, 7% for apples and pears, and 5% for bananas

  • Drinking fruit juice increased risk by 8%

Sugar, Juice

Yin J et al. (2021). Intake of sugar-sweetened and low-calorie sweetened beverages and risk of cardiovascular disease: A meta-analysis and systematic review. Adv Nutr. 12(1): 89–101.

  • A meta-analysis of 19 studies found that 1 serving/day of sugar-sweetened beverages increased risk of cardiovascular disease by 8%

  • Low-calorie sweetened beverages increased risk by 7%

Imamura F et al. (2015). Consumption of sugar sweetened beverages, artificially sweetened beverages, and fruit juice and incidence of type 2 diabetes: systematic review, meta-analysis, and estimation of population attributable fraction. BMJ. 351: h3576.

  • A meta-analysis of 17 studies found that drinking 1 serving/day of sugar-sweetened beverages increased incidence of type 2 diabetes by 7%

  • Risk increased by 8% for artificially-sweetened beverages and 7% for fruit juice

O’Connor L et al. (2015). Prospective associations and population impact of sweet beverage intake and type 2 diabetes, and effects of substitutions with alternative beverages. Diabetologia. 58(7): 1474–1483.

  • An 11-year prospective study of 25,639 individuals found that substituting 1 serving/day of water or unsweetened tea/coffee for soft drinks and sweetened-milk beverages reduced incidence of type 2 diabetes by 14–25%

Boden G et al. (2015). Excessive caloric intake acutely causes oxidative stress, GLUT4 carbonylation, and insulin resistance in healthy men. Sci Transl Med. 7(304): 304re7.

  • 6 normal to overweight men ate 6,206 kcal/day of the common U.S. diet (50% carbohydrates, 35% fat, 15% protein) for 7 days, and this led to an average weight gain of 3.5 kg


Reis CE et al. (2013). Acute and second-meal effects of peanuts on glycaemic response and appetite in obese women with high type 2 diabetes risk: a randomised cross-over clinical trial. Br J Nutr. 109(11): 2015–2023.

  • A randomized cross-over study of 15 women found that eating breakfast with peanut butter lowered total blood glucose response by 18.7%

Ingwersen J et al. (2007). A low glycaemic index breakfast cereal preferentially prevents children’s cognitive performance from declining throughout the morning. Appetite. 49(1): 240–244.

  • A study of 64 children found that a low glycemic-index breakfast prevented declines in attention and memory throughout the morning

Blom WA et al. (2006). Effect of a high-protein breakfast on the postprandial ghrelin response. Am J Clin Nutr. 83(2): 211–220.

  • A single-blind cross-over study with 15 men found that eating a high-protein instead of a high-carbohydrate breakfast lowered total ghrelin response by 45% (ghrelin is a hunger hormone)

  • Total blood glucose concentration was 76% lower over time with high-protein breakfast

Mahoney CR et al. (2005). Effect of breakfast composition on cognitive processes in elementary school children. Physiol Behav. 85(5): 635–645.

  • A study of 30 schoolchildren found that eating oatmeal instead of a high-glycemic breakfast resulted in better cognitive performance

Salad dressing

Goltz SR et al. (2012). Meal triacylglycerol profile modulates postprandial absorption of carotenoids in humans. Mol Nutr Food Res. 56(6): 866–877.

  • A randomized study of 29 subjects found that eating monounsaturated oil with salad doubled absorption of carotenoids vs. polyunsaturated or saturated oil

  • 3 g of canola oil resulted in greater absorption than 20 g of butter

Brown MJ et al. (2004). Carotenoid bioavailability is higher from salads ingested with full-fat than with fat-reduced salad dressings as measured with electrochemical detection. Am J Clin Nutr. 80(2): 396–403.

  • 7 subjects ate salads with 0, 6, or 28 g of canola oil dressing

  • There was essentially no absorption of carotenoids with fat-free dressing

  • A threshold of 6 g of oil was required for optimal absorption


Pauletto P et al. (1996). Blood pressure and atherogenic lipoprotein profiles of fish-diet and vegetarian villagers in Tanzania: the Lugalawa study. Lancet. 348(9030): 784–788.

  • A study of 618 fish-consuming and 645 vegetarian villagers found that a wild-fish diet (300–600 g daily) resulted in a lower incidence of hypertension (2.8% vs. 16.4%) and 14% lower total cholesterol

  • Fish-eaters had over 3X higher levels of omega-3 fats in their blood

Cordain L et al. (2000). Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets. Am J Clin Nutr. 71(3): 682–692.

  • Out of 229 hunter-gatherer societies, 73% derived >50% of subsistence from hunted or fished animal foods

  • No hunter-gatherer society was entirely or largely dependent on gathered plant foods, whereas 20% were highly or solely dependent (86–100%) on hunted or fished animal foods

Omega-3 fats

Schmid-Siegert E et al. (2016). Membranes as structural antioxidants: Recycling of malondialdehyde to its source in oxidation-sensitive chloroplast fatty acids. J Biol Chem. 291(25): 13005–13013.

  • Plant membranes rich in polyunsaturated fatty acids (PUFAs) such as alpha-linoleic acid (ALA) act as supramolecular antioxidants that capture reactive oxygen species, thereby limiting damage to proteins

Anderson EJ at al. (2014). Do fish oil omega-3 fatty acids enhance antioxidant capacity and mitochondrial fatty acid oxidation in human atrial myocardium via PPARγ activation? Antioxid Redox Signal. 21(8): 1156–1163.

  • A study of 32 cardiac surgery patients found that omega-3 supplements for 2–3 weeks increased antioxidant capacity in heart tissue

Hajianfar H, Paknahad Z, Bahonar A. (2013). The effect of omega-3 supplements on antioxidant capacity in patients with type 2 diabetes. Int J Prev Med. 4(Suppl 2): S234–S238.

  • A study of 71 diabetic women found that 8 weeks of omega-3 supplements increased antioxidant capacity by 9%, whereas it dropped by 63% in controls


Griffin G et al. (2020). Vitamin D and COVID-19: evidence and recommendations for supplementation. R Soc Open Sci. 7: 201912.

  • A review of evidence recommended vitamin D supplementation at 800–1,000 IU/day to optimize immune health against COVID-19

Goh YI et al. (2006). Prenatal multivitamin supplementation and rates of congenital anomalies: a meta-analysis. J Obstet Gynaecol Can. 28(8): 680–689.

  • A meta-analysis of 41 studies found that prenatal multivitamins reduced risks of neural tube defects (48%), limb defects (43%), cleft palate (42%), cardiovascular defects (39%), and urinary tract abnormalities (32%)

Yao P et al. (2019). Vitamin D and calcium for the prevention of fracture: A systematic review and meta-analysis. JAMA Netw Open. 2(12): e1917789.

  • A meta-analysis of 6 randomized controlled trials with 49,282 participants found that 400–800 IU of vitamin D combined with 1,000–1,200 mg of calcium per day reduced risks of hip fracture (16%) and any fracture (6%)

Mo M et al. (2019). A systematic review and meta-analysis of the response of serum 25-hydroxyvitamin D concentration to vitamin D supplementation from RCTs from around the globe. Eur J Clin Nutr. 73(6): 816–834.

  • A meta-analysis of 136 studies found that North American adults should take 729 IU of vitamin D per day to reach the recommended blood concentration of 75 nmol/L

  • European adults should take 2,519 IU per day

Kim J et al. (2018). Association of multivitamin and mineral supplementation and risk of cardiovascular disease: A systematic review and meta-analysis. Circ Cardiovasc Qual Outcomes. 11(7): e004224.

  • A meta-analysis of 18 studies with 2,019,862 participants found that multivitamin/mineral supplements did not reduce risks of cardiovascular disease, coronary heart disease, or stroke

Macpherson H, Pipingas A, Pase MP. (2013). Multivitamin-multimineral supplementation and mortality: a meta-analysis of randomized controlled trials. Am J Clin Nutr. 97(2): 437–444.

  • A meta-analysis of 21 studies with 91,074 participants found that multivitamin-multimineral treatment did not reduce risks of all-cause mortality, mortality due to vascular causes, or cancer

Myung S-K et al. (2010). Effects of antioxidant supplements on cancer prevention: meta-analysis of randomized controlled trials. Ann Oncol. 21(1): 166–179.

  • A meta-analysis of 22 randomized controlled trials with 161,045 subjects found that antioxidant supplements did not reduce risk of any cancer, but did increase risk of bladder cancer by 52%

How to start today

Wansink B, Painter JE, Lee Y-K. (2006). The office candy dish: proximity’s influence on estimated and actual consumption. Int J Obes. 30(5): 871–875.

  • A 4-week study with 40 secretaries found that participants ate an average of 2.2 candies more per day when they were in a visible bowl

  • They ate 1.8 candies more when the bowl was placed on their desk vs. 2 meters away

Rubini L, Ozabaci D. (2020, April). Hide the cookie jar: Nudging towards healthy eating. SSRN.

  • A student dining hall in the University of New Hampshire re-located cookies from a main section in plain sight to a corner out of the way, and this reduced cookie consumption by 14%

Shukla AP et al. (2017). Carbohydrate-last meal pattern lowers postprandial glucose and insulin excursions in type 2 diabetes. BMJ Open Diabetes Res Care. 5(1): e000440.

  • 16 diabetic volunteers consumed the same meal on 3 days in random order: carbohydrate first, followed 10 minutes later by protein and vegetables; protein and vegetables first, followed 10 minutes later by carbohydrate; or all components together

  • Blood glucose peaks were 40% lower when all components were eaten together, and 54% lower when carbohydrate was eaten last

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