It’s widely accepted that following a balanced diet is one of the best things we can do for our health. But certain foods are more important at different life stages.
During World War Two, the British government introduced a rationing policy that allowed families a weekly allowance. The idea was to allow people to meet their nutritional needs while ensuring food could be distributed equally across the nation.
Sugar was one of the foodstuffs that was rationed. Individuals were allowed around 8oz (227g) of the sweet stuff per week. Much to their chagrin, children under two years old weren’t allocated any, however.
When sugar rationing ended in 1953, average sugar intake of adults doubled. Little did people know at the time, but this would allow scientists in the future a great opportunity to pinpoint the effects of early sugar consumption on our health.
In a 2025 paper, a global team of researchers poured through the medical records of 63,000 people born in the UK between 1951 and 1956 – when sugar rationing was in full force. They found that children who were exposed to less sugar in the womb and for the first 1,000 days of life were 20% less likely to develop cardiovascular disease in later life; 25% less likely to develop heart failure; and 31% less likely to have a stroke than children who were allowed to stuff their mouths with sweets after rationing ended.
It’s probably not a surprise to learn that this strong relationship between sugar intake and health continues after we’re born. Simply put, eating too many sweet sugary snacks is bad for us no matter what age we are.
But with some other foods, the nutritional benefits depend on what stage of your life you happen to be in. Young babies and infants need plenty of the fats present in dairy and whole milk, for example, but such a diet would not be considered so healthy for someone in their 20s and 30s.
According to Federica Amati, a nutritional scientist at Imperial College London in the UK, children’s high energy demands mean they need foods packed with nutrients.
“In childhood, food is literally building the body and the brain,” says Amati. As well as healthy calories, children also need iron, iodine, and a wide range of vitamins to support immunity, brain development and muscle growth.
This means plenty of fruit and vegetables, wholegrains, beans and lentils, good quality fats including nuts and seeds, and minimal ultra-processed foods.
“From conception through the first 1,000 days and into the school years, children are growing rapidly and laying down most of their future bone mass,” says Amati. “That’s why calcium and vitamin D are priority nutrients at this stage; they’re essential for normal bone development and for achieving a healthy peak bone mass, which reduces the risk of osteoporosis and fractures later in life.”
There’s good evidence that eating the right foods in childhood can benefit health later in life
In practice, Amati says, this means regular sources of calcium – such as milk, yogurt, cheese, calcium-set tofu or fortified plant drinks – and vitamin D, from sun exposure and foods like fish and eggs.
There’s good evidence that eating the right foods in childhood can benefit health later in life. In one 2023 study, researchers looked at the diets of children and compared this to their health as children and young adults. They found that children who met three or more dietary recommendations from the UK’s Eatwell Guide at the age of seven had lower heart disease risk markers at age 24 compared to those who had met none of the requirements.
Teens and 20s
While childhood is an important time, the foods we eat in our teens and 20s can also lay the groundworks for future health. According to Amati, this life stage is when we finish building bones and muscle, and start spending hours studying, working, and socialising – all of which increase nutrient needs.
“Adolescence and early adulthood are another big window of opportunity for nutrition,” says Amati. “In the 20s, growth slows, but it’s still a crucial decade for establishing habits that protect heart and brain health in later life. We see that a lot of the groundwork for cardiovascular disease is already being laid in this age group, even though symptoms appear much later.”
In our teens, the body needs more of several nutrients compared to later adulthood. This includes calcium, vitamin D and iron – which is especially important for those who menstruate. Protein and B vitamins are also important, Amati says.
So what does this diet look like? According to Amati, teens and young adults should follow a largely plant-based diet and avoid ultra-processed foods. So lots of fruit, vegetables, wholegrains, beans, nuts, lentils and seeds. It’s also important to have an adequate amount of protein for every meal, which can also be plant-based, she says.
Studies show that following such a diet doesn’t just benefit the body, it can impact mental health too.
“There’s growing evidence that dietary patterns in adolescence can influence mental health risk – diets high in ultra-processed foods and low in whole plant foods are associated with higher rates of depression and anxiety, while more Mediterranean-style patterns appear protective,” Amati says.
The Mediterranean diet is high in vegetables, legumes, nuts and olive oil, with smaller amounts of fish, dairy and poultry.
A Mediterranean diet may also benefit men and women wishing to start a family, which often happens in a person’s 20s, 30s and 40s. Studies show that the Mediterranean diet can positively influence fertility, while a Western diet – which tends to be high in saturated fat, meat and white carbohydrates – is correlated with both female and male infertility. For women, studies also show that a diet rich in folate may help with fertility treatment. Foods high in folate include dark, leafy greens, sprouts, broccoli and chickpeas.
Middle age
In mid-life, we should be starting to think about optimising our diet for health in later life, according to Elizabeth Williams, professor of human nutrition at the University of Sheffield in the UK.
This is particularly true for women around the age of menopause, “when there is accelerated loss of bone density, sarcopenia [age-related muscle loss] and osteoporosis”, says Williams.
As well as osteoporosis, the menopause is associated with increased risk of obesity, heart disease, and type 2 diabetes. In women of reproductive age, oestrogen acts on the central nervous system to reduce appetite. It also increases the insulin sensitivity and glucose uptake of muscles. However in menopause, less oestrogen flows around the body. As a result, weight – and visceral fat – tends to increase.
As women move into their 40s and 50s, two big nutritional priorities emerge: heart health and bone and muscle health – Federica Amati
However, this risk can be significantly offset by following a good diet. For instance, in a recent population study, researchers looked at the diet and health of more than 100,000 US men and women aged at least 39. They found that a healthy diet consisting of fruits, vegetables, whole grains, unsaturated fats, nuts, legumes and low-fat dairy products was strongly associated with healthy ageing (which they define as living to at least 70 with no chronic disease, and good cognitive and physical function and mental health).
“As women move into their 40s and 50s, two big nutritional priorities emerge: heart health and bone and muscle health,” Amati says. “The menopausal transition is associated with a sharp rise in cardiovascular risk, partly because the loss of oestrogen affects blood lipids, blood vessels and body fat distribution.”
Omega 3 fats – especially the types found in oily fish such as mackerel and salmon – help because they lower the risk factors for heart disease, Amati says, and have anti-inflammatory effects.
Meanwhile Amati recommends a slight increase in protein intake to counter the effects of muscle-mass loss, and following a Mediterranean-style diet for better cardiometabolic health – and possibly gut health and mental health too.
Ultimately, she says, it’s important to aim for a varied, plant-rich, Mediterranean-style diet with sufficient protein, calcium, vitamin D and omega-3s that supports heart, bone and brain health, while limiting ultra-processed foods.
Later life
As we get older, our body composition changes and our energy requirements decline, so we need to consume less calories. However we still need to ensure that we get enough nutrients to maintain bone and muscle strength.
According to Williams, the two main nutrients we should focus on in old age are calcium and vitamin D. Older people who don’t get enough calcium or vitamin D have an increased risk of osteoporosis and fragility fractures. Calcium is found in milk and fortified alternative drinks, hard cheese, yoghurt, sardines, tofu and spinach. Vitamin D-rich foods include oily fish, egg yolk and fortified foods.
Eating enough quality protein is also really important as we age, says Jane Murphy, dietician and co-lead of the Ageing and Dementia Research Centre at Bournemouth University in the UK.
“As we age, our form and functions deteriorate, we lose muscle mass and strength, and need protein to prevent sarcopenia,” she says.
But to ensure our bodies use it properly, protein should be one part of a balanced diet that includes carbohydrates, good quality fats (such as unsaturated fats including olive oil, avocados, nuts and oily fish), and vitamins and minerals, Murphy adds.
People living to 100 seem to be defying many other aspects of ageing common to other people. They have a diverse microbiome that looks different to other older people’s – Mary Ni Lochlainn
As we get older, our microbiomes also shift, characterised by a loss of beneficial bacteria such as Firmicutes and Bifidobacterium, alongside an increase in potentially harmful species like Clostridium. This imbalance is associated with several health conditions, such as Alzheimer’s, stroke and heart disease.
While researchers don’t yet fully understand the gut microbiome in relation to every different disease process, we can learn a lot from centenarians, according to Mary Ni Lochlainn, clinical lecturer in geriatric medicine at King’s College London in the UK.
“People living [to] 100 seem to be defying many other aspects of ageing common to other people,” says Ni Lochlainn. “They have a diverse microbiome that looks different to other older people’s.”
Generally, there isn’t a definition of healthy or unhealthy gut bacteria, as it’s more about having an equilibrium of microbes that work together to promote health. However, a few specific bacterial species have been identified, such as Faecalibacterium prausnitzii, that seem to be protective of health.
People who are ageing well are much more likely have F. prausnitzii, Ni Lochlainn says, but while researchers have established that it has protective, positive qualities, they don’t fully understand how it works. If you want to encourage F. prausnitzii to live in your gut, a diet high in fibre and polyphenols (abundant in fruit and vegetables) is the best way to go.
Having a healthy gut can also help to manage some of the nutrient deficiencies that can be associated with older age, as older people are less good at absorbing vitamins from food than younger people. Studies show that healthy gut bacteria may be able to produce enough B12 for that person’s requirements, while some gut bacteria can also produce folic acid. A healthy gut microbiome may also help to prevent the risk of muscle loss and sarcopenia in old age.
Finally, some supplements may be beneficial in later life. Ni Lochlainn’s research shows that prebiotic supplements – natural compounds which encourage the growth of beneficial microorganisms – can improve cognition over a 12-week period in older adults. Ni Lochlainn’s prebiotics contain inulin, a type of dietary fibre, and fructo-oligosaccharides – sugars found in plants. Other research suggests that elderly people – especially care home residents may benefit from vitamin D supplements.
