Paleo
What it is
A pattern built on an idea about what humans ate before agriculture: meat, fish, eggs, vegetables, fruit, nuts and seeds, and nothing that farming introduced — no grains, legumes, dairy, refined sugar or processed food. The historical claim is contested and irrelevant to the scale; what matters here is the food list, which excludes most cheap energy-dense staples and, with them, most of the ways people over-eat.
How it works in practice
Meat or fish with vegetables at most meals, fruit and nuts between, cooking from whole ingredients because almost nothing packaged qualifies. Carbohydrate falls, not by rule but because bread, pasta, rice, beans and lentils are gone; protein tends to be high for the same reason. Calcium has to come from somewhere other than dairy, and fibre from somewhere other than grains and legumes — vegetables and nuts can do both, but not by accident.
What the evidence shows
A systematic review and meta-analysis of the paleo trials found weight about three and a half kilograms lower than with comparison diets, along with smaller waists. The trials were small, short, and in people with chronic diseases such as type 2 diabetes and metabolic syndrome, and the authors explicitly asked for larger and longer studies before drawing conclusions. In the network meta-analysis of named programmes, paleo sits among the named diets whose differences at twelve months are small and uncertain. The reading is the usual one: the exclusions reduce energy for many people, the deficit does the work, and the ancestral story adds nothing measurable.
Who it tends to suit
People who do well with a short, simple rule rather than a budget; people who cook, can afford meat and fish at every meal, and eat mostly at home; people for whom "no bread, no sugar, no processed food" is the whole problem solved.
How it most often fails
On cost — it is the most expensive pattern on this site — and on the table, where bread, cheese, beans and dessert are all refused. Nutritionally, on calcium and fibre when the vegetables are not deliberate. And on the scale, when nuts, dried fruit and oil fill the space grains left: they are paleo and they are dense.
What to watch
Calcium and fibre; total energy from nuts and oil; and the honesty to notice whether the food list is serving the deficit or replacing it.
In the app
The paleo policy code exists and the planner takes it into account, but its revision has no documented review yet, so the app treats it as context rather than a verified rule; the site will change the wording the day that changes.