Lifestyle & therapies

Diet, graded.

Food is the intervention with the most evidence behind it and the least marketing around it. Each pattern below is graded the same way we grade tests: by whether the evidence ties it to outcomes people actually care about, not to buzzwords.

The short version: 4 of the 14 patterns below grade Strong — Mediterranean diet, Drinking less alcohol, Fibre intake, Sodium (salt) reduction; 8 are Moderate — defensible, but for the right person; 2 grade Weak — thin proof, still widely sold.

Jump to: Strong (4) · Moderate (8) · Weak (2)

Grade

Strong evidence

Randomised trials or very large, consistent cohorts tie this to outcomes people care about: heart attacks, deaths, fractures. Guideline bodies recommend it.

01 Mediterranean diet Eat more vegetables, fruit, beans, nuts, whole grains and olive oil, with fish instead of meat most days. Strong 02 Drinking less alcohol If you drink, drinking less is one of the highest-value changes available, and it costs nothing. Strong 03 Fibre intake Fibre is the part of plant food your gut cannot digest. Strong 04 Sodium (salt) reduction Salt drives up blood pressure, and blood pressure drives heart attacks and strokes. Strong

Grade

Moderate evidence

A real signal with honest limits: consistent associations, or trial endpoints that stop short of outcomes. Reasonable to adopt; do not expect miracles.

05 Adequate protein intake Most adults eat enough protein to survive, but less than the amount linked to keeping muscle as you age. Moderate 06 Cutting ultra-processed food Ultra-processed foods are industrial formulations built from refined substances and additives: soft drinks, packaged snacks, reconstituted meats… Moderate 07 DASH diet DASH stands for Dietary Approaches to Stop Hypertension. Moderate 08 Fish intake Oily fish carries omega-3 fats your heart uses, and eating it once or twice a week is linked to fewer deaths from heart disease. Moderate 09 Nut consumption Nuts are the best-studied snack in nutrition. Moderate 10 Coffee intake Coffee drinkers can relax about their habit. Moderate 11 Caloric restriction Deliberately eating less, by around 12 percent, improved nearly every cardiometabolic marker measured in a rigorous two-year trial. Moderate 12 Plant-based diet Plants deserve more of your plate. Moderate

Grade

Weak evidence

The measured benefits are small, indirect or unproven. Fine because you enjoy it; not something to schedule your life or budget around.

13 Time-restricted eating Eat all your meals inside a window of roughly eight hours and fast for the rest. Weak 14 Ketogenic (very low-carb) diet Cut carbohydrates to roughly 50 grams a day and the body shifts into ketosis, burning fat for fuel instead of glucose. Weak

How to read these grades. They use the same four-step scale as our test reviews, and they answer a different question: whether doing this is worth your time and money, judged on the published evidence in people. A weak grade means the proof is thin, never that we found proof of harm. Read the methodology.

Prefer to start with what a blood test can tell you? All 48 diagnostic tests, ranked →