{"url":"https://whatshealthyandwhy.com/ultra-processed-food/are-ultra-processed-foods-harmful","path":"/ultra-processed-food/are-ultra-processed-foods-harmful","alternates":{"json":"https://whatshealthyandwhy.com/api/articles/ultra-processed-food/are-ultra-processed-foods-harmful.json","markdown":"https://whatshealthyandwhy.com/ultra-processed-food/are-ultra-processed-foods-harmful.md"},"topic":{"slug":"ultra-processed-food","name":"Ultra-Processed Food","url":"https://whatshealthyandwhy.com/ultra-processed-food"},"slug":"are-ultra-processed-foods-harmful","order":1,"title":"Ultra-Processed Food: Harmful or Just Unhealthy?","question":"Are ultra-processed foods harmful, or is it just calories and sugar?","answer":"Likely more than calories and sugar: in a trial people ate about 500 more calories a day on ultra-processed diets, though the category is broad.","description":"What trials and large cohorts show about ultra-processed food, weight and disease, where the NOVA label falls short, and how to eat well without rigid rules.","confidence":3,"confidenceNote":"Two feeding trials found worse intake or weight outcomes on ultra-processed diets, but they were small and short, the cohort links are observational, and the category itself is debated.","evidenceSummary":{"rctCount":3,"observationalCount":3,"metaAnalysisCount":1,"totalParticipants":"9,900,000+","replicated":true,"newestStudyYear":2025},"category":{"categoryTitle":"What's Harming You","categorySlug":"harming-you","subcategoryName":"Hidden Dangers in Food","subcategorySlug":"food-dangers","url":"https://whatshealthyandwhy.com/explore/harming-you/food-dangers"},"actions":["Check the ingredient list: items you would not find in a home kitchen, such as high-fructose corn syrup, hydrogenated oils, flavour enhancers and emulsifiers, mark a product as ultra-processed [5].","Start with the biggest offenders: ready-to-eat processed meats and sugary or artificially sweetened drinks were the ultra-processed groups most tied to higher death rates in two US cohorts [8].","Aim for overall diet quality, not purity: in those cohorts, better diet quality went with lower mortality at every level of ultra-processed food intake [8]."],"cautions":["Eating-disorder history, or anxiety about food? Avoid strict clean-eating rules and talk to a clinician, because extreme diets pursued for health can lead to malnutrition and impaired daily life [12].","If you rely on fortified shakes or soft-texture products for a medical reason, check with a dietitian before replacing them."],"simpleText":"Probably more than the label numbers. In an inpatient trial, ultra-processed meals matched for calories offered, sugar, fibre and salt still led people to eat about 500 more calories a day and gain weight; they lost weight on unprocessed meals [1]. A longer trial found less weight loss on ultra-processed food even when both diets followed healthy guidelines [2]. Large cohorts link high intake to heart disease and early death, but the category is broad and cause is unproven [3][4].","mediumText":"How it works\n\nWhat counts. The NOVA system sorts foods by industrial processing. Ultra-processed foods are formulations built from ingredients rarely used in home kitchens (such as high-fructose corn syrup, hydrogenated or interesterified oils, hydrolysed proteins) or from additives that make them appealing (flavours, colours, emulsifiers, sweeteners, thickeners). A practical test is to look for one of those items in the ingredient list [5]. In the US, these foods supply about 58% of energy and about 90% of the energy from added sugars [6].\n\nWhy they might do more than sugar and calories. In the trial above, meals were matched for presented calories, energy density, macronutrients, sugar, sodium and fibre. People still ate about 508 more calories a day on the ultra-processed diet, from carbohydrate and fat but not protein, and the trial was not designed to show why [1]. Emulsifiers are one lead: in an 11-day feeding study of 16 healthy adults, 15 g a day of carboxymethylcellulose reduced gut microbiome diversity and caused modest abdominal discomfort [7]. See our emulsifiers and thickeners article.\n\nNot all of it is equal. In two US cohorts, the link to mortality was strongest for ready-to-eat meat-based products and sugary or artificially sweetened drinks, and diet quality mattered at any intake level [8]. See our guides to processed meat and sugary drinks.\n\nThe label is contested. Critics say the definition has shifted over time, that nutrient differences between categories are concentrated in sugars and fibre, and that national surveys in two countries found no BMI link [9]. In a published debate, both sides agreed processing affects health but disagreed on whether \"ultra-processed\" adds anything beyond nutrient profiling [10]. A seven-day menu with 91% of calories from ultra-processed foods still scored 86 out of 100 on a diet-quality index, though that was a paper exercise, not a trial [11].\n\nWhat to do. Build most meals from foods that need little more than washing, cooking or freezing: vegetables, fruit, beans, eggs, fish, nuts, oats, plain yoghurt. Treat sweet drinks, processed meats and packaged snacks as the first things to cut back [8], not as a moral test. Aim for a good overall pattern; rigid purity rules can backfire [12].","deepText":"The evidence in detail\n\nFeeding trials\n\nIn the NIH inpatient trial, 20 weight-stable adults (mean age 31, BMI 27) were randomised to ultra-processed or unprocessed diets for 2 weeks, then switched for 2 weeks, eating as much or as little as they liked. Intake was 508 ± 106 kcal a day higher on the ultra-processed diet (P = 0.0001), from carbohydrate (+280 kcal) and fat (+230 kcal) but not protein. Participants gained 0.9 ± 0.3 kg on the ultra-processed diet and lost 0.9 ± 0.3 kg on the unprocessed one [1]. It was small and brief, so it shows intake and short-term weight change, not long-term outcomes.\n\nThe UK trial randomised 55 adults with overweight or obesity who habitually got at least half their energy from ultra-processed food to two 8-week diets that both followed the Eatwell Guide. Both caused weight loss, but more on the minimally processed diet (-2.06%, 95% CI -2.99 to -1.13) than on the ultra-processed diet (-1.05%, -1.98 to -0.13); the difference was -1.01 percentage points (-1.87 to -0.14, P = 0.024). Mild digestive side effects were common on both diets [2].\n\nCohorts and pooled analyses\n\nAn umbrella review of 45 pooled analyses (9,888,373 people) found direct associations with 32 health outcomes. Evidence was graded convincing for cardiovascular death (RR 1.50, 95% CI 1.37 to 1.63) and type 2 diabetes (dose-response RR 1.12, 1.11 to 1.13), and highly suggestive for all-cause mortality (RR 1.21, 1.15 to 1.27); most pooled analyses were rated low or very low quality by GRADE, and all were observational [3]. In NutriNet-Santé (105,159 adults, median follow-up 5.2 years), each 10-point rise in the share of ultra-processed food was linked to 12% more cardiovascular disease (HR 1.12, 1.05 to 1.20), unchanged after adjusting for saturated fat, sodium, sugar and fibre [4].\n\nA longer US analysis (74,563 women and 39,501 men, 30 to 34 years, 48,193 deaths) found the highest versus lowest quarter had only 4% higher all-cause mortality (HR 1.04, 1.01 to 1.07), driven by non-cancer, non-cardiovascular causes, with no link to cancer or cardiovascular death. Meat-based ready-to-eat products carried hazard ratios of 1.06 to 1.43, sugary and artificially sweetened drinks 1.09, dairy desserts 1.07 and breakfast foods 1.04; better diet quality was linked to lower mortality within every quarter of ultra-processed intake [8].\n\nMechanisms and exposure\n\nIn NHANES 2009-2010 (9,317 people), ultra-processed foods provided 57.9% of energy and 89.7% of energy from added sugars; added sugars rose from 7.5% of energy in the lowest quintile to 19.5% in the highest [6]. The emulsifier study compared 7 people on carboxymethylcellulose with 9 on an emulsifier-free diet; it lowered short-chain fatty acids, and 2 participants showed bacteria encroaching on the gut's inner mucus layer, but the sample was tiny [7].\n\nWhere the evidence disagrees\n\nThe cohort effects are modest and inconsistent across outcomes (cardiovascular disease in one cohort, no cardiovascular mortality link in another) and rest on food-frequency or diet-record data that must be sorted into NOVA groups [4][8]. Critics argue the category is poorly defined, misclassifies foods and is confounded with obesity-prone lifestyles, whereas supporters note associations persist after nutrient adjustment [9][10]. Both feeding trials were short, and the second showed weight loss on both diets [2]. A healthy-pattern menu made mostly of ultra-processed foods was feasible on paper but lacked vitamin D, vitamin E and choline [11].\n\nBottom line (confidence 3 of 5). Ultra-processed diets probably drive overeating and slightly worse health, but \"ultra-processed\" lumps together very different foods. Eat mostly whole foods, cut the worst offenders first, and avoid turning food rules into a source of anxiety.","deepTruncated":false,"references":[{"id":"1","title":"Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake","authors":"Hall KD, Ayuketah A, Brychta R, et al.","year":2019,"journal":"Cell Metab","pmid":"31105044","url":"https://pubmed.ncbi.nlm.nih.gov/31105044/"},{"id":"2","title":"Ultraprocessed or minimally processed diets following healthy dietary guidelines on weight and cardiometabolic health: a randomized, crossover trial","authors":"Dicken SJ, Jassil FC, Brown A, et al.","year":2025,"journal":"Nat Med","pmid":"40760353","url":"https://pubmed.ncbi.nlm.nih.gov/40760353/"},{"id":"3","title":"Ultra-processed food exposure and adverse health outcomes: umbrella review of epidemiological meta-analyses","authors":"Lane MM, Gamage E, Du S, et al.","year":2024,"journal":"BMJ","pmid":"38418082","url":"https://pubmed.ncbi.nlm.nih.gov/38418082/"},{"id":"4","title":"Ultra-processed food intake and risk of cardiovascular disease: prospective cohort study (NutriNet-Santé)","authors":"Srour B, Fezeu LK, Kesse-Guyot E, et al.","year":2019,"journal":"BMJ","pmid":"31142457","url":"https://pubmed.ncbi.nlm.nih.gov/31142457/"},{"id":"5","title":"Ultra-processed foods: what they are and how to identify them","authors":"Monteiro CA, Cannon G, Levy RB, et al.","year":2019,"journal":"Public Health Nutr","pmid":"30744710","url":"https://pubmed.ncbi.nlm.nih.gov/30744710/"},{"id":"6","title":"Ultra-processed foods and added sugars in the US diet: evidence from a nationally representative cross-sectional study","authors":"Martínez Steele E, Baraldi LG, Louzada ML, et al.","year":2016,"journal":"BMJ Open","pmid":"26962035","url":"https://pubmed.ncbi.nlm.nih.gov/26962035/"},{"id":"7","title":"Randomized Controlled-Feeding Study of Dietary Emulsifier Carboxymethylcellulose Reveals Detrimental Impacts on the Gut Microbiota and Metabolome","authors":"Chassaing B, Compher C, Bonhomme B, et al.","year":2022,"journal":"Gastroenterology","pmid":"34774538","url":"https://pubmed.ncbi.nlm.nih.gov/34774538/"},{"id":"8","title":"Association of ultra-processed food consumption with all cause and cause specific mortality: population based cohort study","authors":"Fang Z, Rossato SL, Hang D, et al.","year":2024,"journal":"BMJ","pmid":"38719536","url":"https://pubmed.ncbi.nlm.nih.gov/38719536/"},{"id":"9","title":"Ultra-Processed Foods: Definitions and Policy Issues","authors":"Gibney MJ","year":2019,"journal":"Curr Dev Nutr","pmid":"30820487","url":"https://pubmed.ncbi.nlm.nih.gov/30820487/"},{"id":"10","title":"Does the concept of ultra-processed foods help inform dietary guidelines, beyond conventional classification systems? Debate consensus","authors":"Astrup A, Monteiro CA","year":2022,"journal":"Am J Clin Nutr","pmid":"36253965","url":"https://pubmed.ncbi.nlm.nih.gov/36253965/"},{"id":"11","title":"Dietary Guidelines Meet NOVA: Developing a Menu for A Healthy Dietary Pattern Using Ultra-Processed Foods","authors":"Hess JM, Comeau ME, Casperson S, et al.","year":2023,"journal":"J Nutr","pmid":"37356502","url":"https://pubmed.ncbi.nlm.nih.gov/37356502/"},{"id":"12","title":"On orthorexia nervosa: A review of the literature and proposed diagnostic criteria","authors":"Dunn TM, Bratman S","year":2016,"journal":"Eat Behav","pmid":"26724459","url":"https://pubmed.ncbi.nlm.nih.gov/26724459/"}],"wordCount":1035,"source":{"path":"src/content/topics/ultra-processed-food/are-ultra-processed-foods-harmful.md"},"citeAs":"“Are ultra-processed foods harmful, or is it just calories and sugar?.” What's Healthy and Why. https://whatshealthyandwhy.com/ultra-processed-food/are-ultra-processed-foods-harmful","notice":"General information backed by peer-reviewed research, not medical advice."}