How many fruits and vegetables do I actually need per day?
Five portions of fruit and vegetables per day (two pieces of fruit, three serving-spoon scoops of vegetables) is the number with the strongest evidence base; eating more does not provide additional benefit, but most people do not even reach this minimum.
Five portions of fruit and vegetables per day is the number that emerges most strongly from large-scale research. A meta-analysis of 26 studies involving nearly 1.9 million participants found a 13% lower risk of death at that amount compared with just 2 portions. The benefit for the heart was 12% lower mortality; the largest effect was seen for lung diseases, where the risk was 35% lower. More than 5 portions provided no additional benefit.
Not every portion counts equally. Fruit juice and potatoes were not associated with a lower risk of death in the same study, and the same applied to starchy vegetables such as peas and corn. The benefit came from regular vegetables and whole fruit. That distinction is practical: a glass of orange juice at breakfast counts differently from an orange.
What do 5 portions look like in practice? Think of roughly two pieces of fruit and three serving-spoon scoops of vegetables, spread throughout the day. Approximately 80 grams per portion is a commonly used benchmark. Berries and leafy greens are regularly described in research as beneficial choices, partly because of polyphenols, compounds that may have an anti-inflammatory effect.
Most people fall well short of those 5 portions. In American research, in 2019 fewer than 13% of people ate enough fruit and fewer than 10% ate enough vegetables. A further problem is that well over half of the people who eat too few vegetables believe they are already eating enough. That makes improvement harder.
Concerns about substances in vegetables that might inhibit nutrient absorption, such as lectins or oxalates, are not a reason for healthy people to eat less. A review study concludes that the health risk from these substances at normal intake levels is negligible. Only in the case of specific medical conditions may it be worth being somewhat more cautious about them.
All claims are based on observational research (cohorts and meta-analyses); a causal relationship is likely but not proven. The smallest study (n=38, gestational diabetes) is not representative of the general question and has only been used in passing.
How many vegetables do you really need per day?
Five servings of vegetables and fruit per day offers the best protection, with non-starchy vegetables counting and juice and potatoes not. More than five servings adds nothing.
How much water do I really need to drink per day?
There is no magic number: for a healthy adult who is not very active, thirst is a reliable guide, with a total fluid intake of roughly 2 to 3 litres per day from all sources as a reference point. Drink more as soon as you exercise, when it is warm, or as you get older.
How much fibre do I need and why?
Aiming for 25 to 29 grams of fibre per day is well supported and delivers the greatest health benefit. Most people in Western countries fall far short of that, so eating more vegetables, legumes and whole grains is a smart move for almost everyone.
Does the order in which you eat food and vegetables during a meal matter?
Eating vegetables and/or protein first and carbohydrates last demonstrably blunts the post-meal blood sugar spike, even in healthy people. It is a small adjustment with no downsides that you can simply try out.
How much iron do you need per day?
For healthy adults without a deficiency, compensating for 1 to 2 mg of iron per day through a varied diet is sufficient; if you have a demonstrated deficiency or are pregnant, the requirement is much higher and it is best discussed with your doctor.
How much vitamin D should you take per day?
For healthy adults under 75, extra vitamin D is probably not necessary, but for children, people aged 75 and older, pregnant women, and those at high risk of diabetes, supplementation is worthwhile. If you are unsure whether you belong to a risk group, it is worth discussing this with your general practitioner.