Eating constantly throughout the day may be accelerating your ageing process. With food available at almost any hour, many people spend all of their waking hours grazing on meals, snacks and desserts. Yet researchers have found that this pattern of near-continuous eating could be doing more harm than good.
As soon as food enters the bloodstream in the form of glucose, it triggers the release of insulin. This hormone activates a cellular switch that drives cell growth and proliferation – a mechanism essential for survival, but one that becomes dangerous when overstimulated. Too much cell proliferation increases the chance of random DNA mutations, raises the long-term risk of cancer and fuels the growth of visceral fat, a damaging form of internal fat. Eric Verdin, president and CEO of the Buck Institute for Research on Aging in Novato, California, explains that the body needs time away from eating to focus on repair. “There is a lot of evidence for this – 12 hours fasting and repairing, and 12 hours eating and building is more conducive to healthy ageing,” he says.
The hidden damage of advanced glycation end products
One of the most potent drivers of ageing is a group of toxins called advanced glycation end products, or AGEs. These compounds are responsible for many of the visible and internal signs of ageing: wrinkles, stiffness, cataracts, loss of heart elasticity and even Alzheimer’s disease. AGEs form during a chemical process known as glycation, in which sugars in the body react with proteins or fats. The process is particularly destructive when it targets collagen – the protein that gives skin its youthful elasticity – turning it into a drier, stiffer form. “AGEs change protein structure and, at the same time, cause a large amount of inflammation,” says Jaime Uribarri, a kidney doctor at the Icahn School of Medicine at Mount Sinai in New York and a leading expert on AGEs.
Glycation accelerates when there is excess sugar in the bloodstream, which occurs after consuming sweets containing rapidly absorbed fructose or easily digestible refined carbohydrates such as white rice, white pasta and pizza dough. But AGEs are not only generated inside the body; they are also created within foods themselves, particularly those high in protein and fat – such as meat, cheese and fish – when they are grilled, barbecued or fried at high temperatures. Uribarri’s research highlights the scale of the problem: just three slices of bacon fried for five minutes contain 91,577 AGEs, compared with only 23 AGEs in a tomato. To limit AGE accumulation, experts recommend eating more whole grains such as brown rice, and using slow-cooking or stewing methods instead of grilling.
How saturated fat and fibre shape immune ageing
The immune system is also vulnerable to dietary choices. Saturated fat – found primarily in animal products such as red meat, cheese and ice-cream – is broken down into ceramides, compounds that can reprogramme immune cells in the gut into a more inflammatory state. This can make the gut wall leaky, allowing microbes and toxic metabolites to seep into the bloodstream and accelerate immune ageing over time. Niharika Duggal, an assistant professor in the University of Birmingham’s department of inflammation and ageing, says: “We’ve found that two of the biggest dietary features associated with immune ageing are higher consumption of saturated fat and lower consumption of fibre.” The good news is that the gut can handle some saturated fat if it is balanced with enough fibre and omega-3s. Scientists recommend consuming the equivalent of 1g of omega-3s per day – achievable by eating one mackerel fillet or two to three salmon fillets once a week – and at least 40g of fibre, found in whole grains and legumes.
B vitamins: the unsung regulators of cellular repair
B vitamins play a crucial role in healthy ageing. The body uses vitamin B3 – found in turkey, tuna and anchovies – to produce NAD+, a molecule essential for cellular energy and repair. While NAD+ supplements are commercially popular, the body can make it naturally from food. More broadly, B vitamins are required to produce methyl donors, chemicals that help turn genes on or off at the right times. This includes keeping tumour suppressor genes active, which defends against cancer. Without sufficient methyl donors, this gene regulation becomes less controlled with age. Vitamin B12, present in salmon, tuna, beef, eggs and dairy, is equally important. Deficiency can lead to a leaky gut, memory loss and slower brain processing speeds. For anyone over 50 experiencing signs of cognitive decline, checking B12 status is particularly important.
The acid load from modern diets
Another overlooked factor is the acidity of our diet. Protein, added salt and phosphoric acid – a common preservative and flavour enhancer in ultra-processed foods – are metabolised into acidic substances. Meanwhile, most people do not eat enough potassium-rich fruits, vegetables and dried herbs to counterbalance these acids. Over years, this places increasing stress on the kidneys, the body’s main acidity regulator. Lynda Frassetto, a kidney specialist and professor at the University of California, San Francisco, warns: “As your kidneys fail, your ability to get rid of these acids goes down, so the problem gets progressively worse.” Ageing researchers advise aiming for twice as much fruit and vegetables as protein with each meal.
Healthy fats and the fight against frailty
Omega-3 fatty acids, found in oily fish and available as low-cost supplements, are among the most potent anti-ageing tools. They help resolve gut inflammation caused by saturated fat, support brain and heart health, retune the immune system, and regulate muscle mass. Crucially, omega-3s can prevent an age-related condition called anabolic resistance, which impairs the body’s ability to build new muscle fibres from dietary protein and accelerates frailty. Consuming the equivalent of 1g of omega-3s per day has been linked with slowing biological ageing, yet most people fall far short of this amount.
Phytochemicals that stimulate the brain’s immune cells
Brightly coloured fruits and vegetables contain phytochemicals that may protect against cognitive decline. Alzheimer’s Research UK has highlighted studies showing that people who consume more of these compounds have a lower risk of cognitive decline. Specific examples include passion fruit, pomegranates, strawberries, grapefruit, tomatoes and various teas. Ageing experts believe that when the body metabolises these fruits, they may rev up the brain’s immune cells, prompting them to work more efficiently to clear toxins and promote repair.
The timing of meals matters
When you eat may be as important as what you eat. Most people eat their biggest meal in the evening, but shifting that pattern could be beneficial. Large meals at night disrupt sleep – a vital time for bodily repair – and load the body with calories when metabolism is at its slowest. Satchin Panda, a professor at the Salk Institute in San Diego, California, explains: “Our insulin sensitivity is much better in the first half of the day. This allows us to manage [the blood sugar rise after eating a meal] much better.”
A sample longevity menu
A low-calorie, nutrient-dense menu that concentrates protein-heavy meals earlier in the day can support healthy ageing. One example includes a breakfast of egg, spinach and mushroom muffins; a lunch of smoked mackerel salad for a heavy dose of omega-3s; a dinner of chickpea, spinach and coconut curry with brown rice and cauliflower; and a snack of one medium pear with three tablespoons of walnut halves, plus two cups of green tea. This menu provides two portions of leafy greens rich in vitamin K, helps minimise dietary acid load, and delivers between 40 and 50 grams of fibre to nourish the gut and immune system.