Healthy eating: what does science actually say?

The internet offers a thousand opinions on what's "healthy." One day eggs are great, the next they're poison. Fat was the enemy, now it's the savior. The truth is less dramatic — but much clearer when you look at the full picture.

What do we know with high certainty?

The largest and most reliable study on dietary patterns to date was published in Nature Medicine (Wang et al., 2023). It analyzed multiple prospective cohorts with over 200,000 participants across decades of follow-up. The conclusion: there is no single optimal diet — but there are multiple dietary patterns that consistently reduce the risk of chronic diseases. All share common features: high intake of vegetables, fruits, whole grains, legumes, nuts and fish, and low intake of processed food, red meat and sweetened beverages.

The comprehensive Global Burden of Disease analysis (GBD, 2019) found that diet is responsible for more premature deaths than any other risk factor — more than smoking, high blood pressure, or physical inactivity. The most important dietary risk factors: low intake of whole grains, fruits and nuts, and excessive sodium intake.

Processed food: the silent problem

Ultra-processed food (UPF) — industrially manufactured products high in additives, preservatives, sweeteners and flavor enhancers — has become a subject of serious scientific attention in recent years.

An umbrella review in the BMJ (Lane et al., 2024) analyzed 45 meta-analyses and found that high ultra-processed food consumption was associated with higher risk for 32 of 45 examined health outcomes, including cardiovascular disease, colorectal cancer, type 2 diabetes, depression, and all-cause mortality.

An updated meta-analysis in Systematic Reviews (Liang et al., 2025), based on 18 prospective cohort studies with 1,148,387 participants, confirmed that those with the highest ultra-processed food consumption had a 15% higher risk of all-cause mortality compared to the lowest consumers. Each 10% increase in the share of ultra-processed food in the diet was associated with a 10% higher risk of death.

A three-part Lancet Series (November 2025) confirmed that ultra-processed food is globally displacing traditional dietary patterns, deteriorating diet quality, and contributing to the chronic disease epidemic.

Alcohol: less is better

For decades, the belief held that moderate drinking (1–2 glasses of wine daily) benefited the heart. Newer research challenges this.

A comprehensive meta-analysis in JAMA Network Open (Zhao et al., 2023) analyzed 107 prospective studies with over 4.8 million participants and found that no amount of alcohol is associated with reduced risk of all-cause mortality. Previous studies showing a protective effect of moderate drinking had methodological flaws — they didn't properly separate former drinkers (who stopped due to health issues) from lifetime abstainers.

The Global Burden of Disease study (GBD Alcohol, 2024) confirmed that alcohol is a risk factor for more than 60 diseases and conditions, including liver disease, cancer (oral, throat, esophageal, liver, breast, colorectal), cardiovascular disease, and neurological disorders.

The WHO in its latest guidelines (2023) clearly states: "The best choice for health is not to drink alcohol. No amount is safe."

What to eat, then?

Instead of following trends or extreme diets, focus on what science has consistently confirmed across decades:

More: Vegetables and fruits (diverse colors), whole grains, legumes (beans, lentils, chickpeas), nuts and seeds, fish (especially fatty — salmon, sardines, mackerel), olive oil as primary fat source.

Moderate: Eggs, poultry, fermented dairy (yogurt, kefir, cheese), red meat (1–2x per week, not daily).

Limit: Ultra-processed food, sweetened beverages, industrial pastries, processed meat products, excessive added sugar and salt.

Avoid: Daily alcohol and high amounts of trans fats (industrially hydrogenated oils).

Moderation as a long-term strategy

After everything we know, the recipe for healthy eating is surprisingly simple: eat mostly unprocessed food, as diverse as possible, in moderate amounts. It's not a sexy headline, but it's the only strategy that science consistently confirms across decades — and one you can maintain for life.

An occasional pizza, dessert, or glass of wine won't ruin your health. But daily consumption of ultra-processed food and regular alcohol will. The difference between the two is habit — and habits change slowly, step by step.

Instead of searching for the perfect diet, find a good enough diet you can actually sustain. That's the only approach that works long-term.

References

• Barbaresko, J. et al. (2025). Ultra-processed food consumption and human health: an umbrella review of systematic reviews with meta-analyses. Critical Reviews in Food Science and Nutrition, 65(11), 1999–2007.
• Dai, S. et al. (2024). Ultra-processed foods and human health: an umbrella review and updated meta-analyses of observational evidence. Clinical Nutrition, 43, 1386–1394.
• GBD 2019 Risk Factors Collaborators (2020). Global burden of 87 risk factors in 204 countries and territories, 1990–2019. The Lancet, 396(10258), 1223–1249.
• GBD 2020 Alcohol Collaborators (2024). Population-level risks of alcohol consumption. The Lancet, 403(10435), 1437–1452.
• Lane, M.M. et al. (2024). Ultra-processed food exposure and adverse health outcomes: umbrella review of epidemiological meta-analyses. BMJ, 384, e077310.
• Liang, S. et al. (2025). Ultra-processed foods and risk of all-cause mortality: an updated systematic review and dose-response meta-analysis. Systematic Reviews, 14(1), 53.
• Monteiro, C.A. et al. (2025). Ultra-processed foods and human health: the main thesis and the evidence. The Lancet (3-part Series).
• Nilson, E.A.F. et al. (2025). Premature mortality attributable to ultraprocessed food consumption in 8 countries. American Journal of Preventive Medicine, 68, 1091–1099.
• Sotos-Prieto, M. et al. (2017). Association of changes in diet quality with total and cause-specific mortality. New England Journal of Medicine, 377, 143–153.
• Wang, P. et al. (2023). Optimal dietary patterns for prevention of chronic disease. Nature Medicine, 29, 719–728.
• WHO (2023). No level of alcohol consumption is safe for our health.
• Zhao, J. et al. (2023). Association between daily alcohol intake and risk of all-cause mortality: a systematic review and meta-analyses. JAMA Network Open, 6(3), e236185.