Fundamentals › Fundamental 3 of 6
Real food most of the time
Most of what you eat should be food with a short ingredient list. Not a ban on anything. A shift in what fills the cart, because ultra-processed food is engineered to be eaten past full.
What you need to do
Build most meals from foods you could name the ingredients of: meat, fish, eggs, dairy, beans, vegetables, fruit, potatoes, rice, oats, nuts, olive oil. Treat packaged snacks, sweetened drinks and fast food as the thing to shrink, not the thing to feel guilty about.
- Added sugar: under about 25 g a day for women, 36 g for men. One sweetened soda spends the whole allowance.
- Sugary drinks are the first thing to swap. Liquid calories do not register as food.
- Fat is not the enemy. Olive oil, nuts, fish and avocado are food. Fried and packaged food is where the fat you do not want lives.
- Nothing is forbidden. A plan you can keep next year beats a perfect plan you quit in March.
Challenges that build this
What the research says
In the only fully controlled inpatient trial, people offered ultra-processed meals ate about 500 calories a day more than on matched minimally processed meals, and gained weight instead of losing it [55]. Even when both diets met healthy-eating guidelines, eight weeks of minimally processed food lost about twice the weight [56]. Across about ten million people, ultra-processed food is linked with 32 adverse outcomes, most strongly early death and heart disease [57]. One to two sugary drinks a day was tied to 26% higher diabetes risk [61] [60].
On fats: replacing saturated fat with unsaturated fat cut cardiovascular events by about 17% across 12 trials [63], and a Mediterranean pattern with olive oil or nuts cut major events by about 30% [64]. Seed oils do not raise inflammation in trials; they are simply the fat in fried and ultra-processed food [66]. A fish-oil capsule did not prevent heart disease in 25,871 adults, so eat the fish rather than the pill [65].
The honest part
The honest mechanism is not 'chemicals'. Ultra-processed foods are energy-dense, soft, fast to eat and built to be over-eaten. Say that, and the fix is obvious: slow food, real food, most of the time [55].
Sources on this page
- Hall 2019, Cell Metab. Living in a research unit, people offered ultra-processed meals ate about 500 calories a day more than on matched minimally processed meals, and gained weight instead of losing it.
- Dicken 2025, UPDATE trial, Nat Med. Even when both diets met healthy-eating guidelines, eight weeks of minimally processed food lost about twice the weight of the ultra-processed version. The gap is smaller when the processed diet is otherwise healthy, but it is still there.
- Lane 2024, BMJ. 45 meta-analyses, about 10 million people: ultra-processed food is linked with 32 adverse outcomes, most strongly early death, heart disease and depression. Observational, but consistent.
- Malik 2010, Diabetes Care. One to two sugary drinks a day was tied to 26% higher risk of type 2 diabetes. Liquid calories do not register as food, so nothing gets eaten less later.
- American Heart Association, added sugars. Added sugar limit: about 25 g a day for women, 36 g for men. One sweetened soda spends the whole allowance.
- Hooper 2020, Cochrane. Replacing saturated fat with unsaturated fat cut cardiovascular events by about 17% across 12 trials of 53,758 people.
- Estruch 2018, PREDIMED, N Engl J Med. A Mediterranean pattern with olive oil or nuts cut major cardiovascular events by about 30%. The trial was retracted for randomisation flaws and republished with the conclusions intact.
- Seed oils scoping review 2026, Crit Rev Food Sci Nutr. Trials show seed oils do not raise inflammation, and higher linoleic acid intake is linked with lower heart risk. The kernel of truth: they are the fat in fried and ultra-processed food.
- Manson 2019, VITAL, N Engl J Med. In 25,871 adults, a daily fish-oil capsule did not prevent heart disease or cancer overall. Eat the fish; the capsule is optional.