7 eating habits that make a real difference after 40

Building healthy eating patterns after forty is a matter of small habits layered on top of one another. Some are surprisingly straightforward; others require a genuine shift. The Nutrition & prevention page has the full picture; this piece focuses on the seven habits with the strongest evidence behind them.

Five portions of fruit and vegetables a day is the magic minimum

Two pieces of fruit and three generous servings of vegetables a day: that is the figure that emerges from a study of nearly 1.9 million participants as the point at which the health benefit is greatest. Eating more does not add further gains. Fruit juice and potatoes do not count. The problem is that most people already fall short of this minimum, so almost everyone has immediate room to improve. See also how much fruit and vegetables you actually need each day.

You probably need more protein than you think

The standard guideline of 0.8 grams of protein per kilogram of body weight is likely too low for people over forty. After forty, your muscles become more vulnerable to loss and respond less strongly to protein after a meal. Aim instead for 1.0 to 1.2 grams per kilogram per day, spread evenly across meals, and combine that with strength training. That combination has the best evidence behind it. Read more about why older adults need more protein.

Start your meal with vegetables or protein, finish with carbohydrates

The order in which you eat matters. Multiple studies show that starting with vegetables or protein substantially blunts the blood sugar spike after a meal – even in people without diabetes. Carbohydrates such as bread, pasta or rice come last. It is a small adjustment with no downsides, no expensive supplement or complicated protocol required. You can find details on the research at the order in which you eat your food.

Give yourself an overnight fast of at least 12 hours

When you eat matters as much as what you eat. Research involving tens of thousands of people suggests that an overnight eating break of 12 to 13 hours is associated with a lower biological age and a reduced risk of chronic disease. An eating window of eight hours or shorter, on the other hand, does not appear to offer any additional benefit and may even be harmful. In practice: close the kitchen early in the evening and do not eat breakfast too soon after waking. Whether this is a causal relationship has not yet been established in humans, but the findings consistently point in the same direction. More on this at meal timing and how long you live.

Concentrate your meals during the day, and earlier rather than later

Late eating does not sit well with your body clock, which becomes less flexible after forty. Keeping your meals to the daytime is associated with fewer health risks and slower biological ageing. Night shifts or a busy social life can make this harder, but even shifting your evening meal a little earlier helps. Read about how the timing of your meals affects how quickly you age.

Favour a predominantly plant-based diet, but do not be rigid about it

People who eat mostly plant-based foods tend to live longer on average, but that advantage comes from the overall quality of the diet, not from the label "vegetarian" or "vegan". People who occasionally eat fish or meat but otherwise get plenty of vegetables, legumes, nuts and whole grains do at least as well in the studies. For older adults and those with higher nutritional needs, a strictly vegan diet also carries real risks of deficiencies in vitamin B12, iron and calcium.

Get your fibre from your plate, not a supplement

More fibre from vegetables, fruit and whole grains reduces the risk of constipation, a complaint that becomes more common after forty. Large-scale research shows that a Mediterranean or plant-based eating pattern works more reliably than simply focusing on fibre intake alone. Psyllium fibre supplements are an option when diet alone is not enough, but you need to drink plenty of water alongside them: for people who do not drink much, they are not always the safest choice.

What the evidence does not support: NAD+ supplements as a nutritional booster

NR and NMN supplements are sold as a way to maintain your NAD+ levels and thereby slow ageing. They do raise those levels measurably, but whether that also leads to less disease or a longer life in humans has not been shown. The only approach for which both higher NAD+ levels and broader health benefits have been demonstrated is regular exercise. Ordinary food also provides building blocks for NAD+, but how much that contributes is not yet known. Until better evidence is available, exercise is the smarter investment.