Ultra-processed food: the everyday poison that oxidises cells
A convenience-store breakfast, a delivery lunch, three minutes in the microwave for dinner. In one ordinary day dozens of sweeteners, emulsifiers, colourings and preservatives enter the body. A review in the BMJ in February 2024, covering around ten million people, found that the more ultra-processed food people ate, the more of 32 health problems appeared.
The term comes from the NOVA classification of the Brazilian nutrition scientist Carlos Monteiro. Ultra-processed food sits at the top of that ladder, and by weight it carried on average four times the calories of minimally processed food: 378 against 94 per 100 g.
The surge of chronic disease in the young
In a Korean national study, children and teenagers with obesity took a quarter of their daily energy from ultra-processed food, and the heaviest consumers had 1.75 times the risk of fatty liver and 2.44 times the risk of insulin resistance. Type 2 diabetes under the age of 30 rose about fourfold in thirteen years.
Genes do not change in a few decades, the author notes. Daily life does: less movement, sweeter drinks, more processed food, and a shorter span of healthy years.
The truth about cooking oil
Soy, corn and rapeseed oils are pressed under heat, extracted with hexane and refined in four steps at up to 240 to 270 °C. The author argues the oil has already oxidised once before it reaches the kitchen, and frying at home adds trans fats and oxidation products.
The deeper issue he names is omega-6. The ideal omega-6 to omega-3 ratio is around 1 to 4:1, while the modern diet runs at 15 to 20:1. The book is careful to say that findings on omega-6 and dementia are mixed, and that the ratio matters more than the amount.
Food additives and the gut microbiome
Around a hundred trillion microbes live in the gut as allies in digestion and immunity. Additive safety testing, the author says, checks one substance at a time, for a short period, in a clean lab, while people eat dozens together: the cocktail effect.
Heavy ultra-processed food intake was linked to 40% less microbial diversity, and the emulsifier CMC widened the gaps between gut wall cells two to threefold. Through those gaps, toxins can reach the blood.
Endocrine disruptors in plastics and detergents
Thermal receipts, hot food in plastic tubs and can linings carry bisphenol A; cosmetics and detergents carry phthalates. In 2018 Korea’s Ministry of Food and Drug Safety named fourteen bisphenols, parabens and phthalates for its first integrated risk assessment.
The book also introduces obesogens, chemicals that promote weight gain. They act in tiny amounts, dissolve in fat and linger in the body.
How chemicals scramble the hormone system
If a hormone is a key, its receptor is the lock. An endocrine disruptor is a counterfeit key that opens the wrong door or jams the right one; BPA, shaped like oestrogen, binds its receptor. A Seoul National University analysis linked Korean adults’ phthalate and BPA exposure to effects on thyroid hormone.
One hormone out of balance can topple metabolism, reproduction and immunity like dominoes.
The health foods we believed in
A 1950s graph tying fat to heart disease shaped decades of dietary advice, and sugar and refined carbohydrate filled the space fat left. The author treats obesity as a hormone problem: 100 calories of sugar, which spikes insulin, behave differently from 100 calories of olive oil. In 2016 it emerged that a 1967 Harvard team had taken sugar-industry money.
The book separates honest mistakes from deliberate distortion and calls neither a conspiracy. What it offers is not a fixed diet but the habit of asking why we were told what we were told.
Questions this chapter answers
What is ultra-processed food?
Food in NOVA group 4: ingredients broken down and reassembled with additives. Instant noodles, snacks, soft drinks, processed meat and ready meals all belong here.
Do I have to cut out processed food completely?
The book says that is neither realistic nor necessary. Start by buying a little less of the products whose labels list long strings of unfamiliar chemicals.
Why are seed oils linked to inflammation?
The author points to oxidation from high-heat refining and reheating, and to a diet whose omega-6 to omega-3 ratio has tipped to 15 to 20:1. He also notes that evidence on omega-6 alone is mixed.
What are the easiest ways to cut exposure to endocrine disruptors?
Keep hot food out of plastic, decline paper receipts where you can, and prefer glass or stainless steel to cans and cling film.
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References from the book
- 영국 의학저널(BMJ), 초가공식품과 32가지 건강 문제 연관성 메타분석, 2024년 2월.
- 영국 영양학 저널(British Journal of Nutrition), 초가공식품 열량 비교 연구, 2024년 1월.
- 질병관리청 국립보건연구원, 「비만 아동·청소년에서 초가공식품 섭취와 대사질환 위험」, 2024년 11월.
- 질병관리청 국립보건연구원, 30세 미만 제2형 당뇨병 유병률 연구, 2025년 8월(2008년 10만 명당 73.3명 → 2021년 270.4명).
- 한국식생활문화학회지, 「가열조건에 따른 유지의 트랜스지방산 생성과 산패도 측정에 관한 연구」, 2008년.
- 앨버타대학교, 초가공식품과 장내 미생물 다양성 연구, 2019년(다량 섭취자 미생물 다양성 40% 감소).
- 코넬대학교, 카복시메틸셀룰로오스(CMC)와 장벽 손상 연구, 2016년(투여 시 장벽 세포 간격 2~3배 확대).
- 식품의약품안전처, 인체적용 제품 및 물질의 통합 위해성 평가, 2018년(1단계 평가 대상물질 14종: 비스페놀류 3종, 파라벤류 4종, 프탈레이트류 7종).
- 서울대학교 보건환경연구소, 「한국 성인의 프탈레이트 및 비스페놀 A 노출수준과 내분비계 영향과의 관계」, 2014년.
- Kearns CE, Schmidt LA, Glantz SA, "Sugar Industry and Coronary Heart Disease Research: A Historical Analysis of Internal Industry Documents", JAMA Internal Medicine, 2016(1967년 하버드 연구팀의 제당업계 자금 수수).
