Health and fitness: The truth about your daily health targets

Eat right, brush regularly, exercise frequently, get enough water … it's all a bit exhausting. So what is fact and what's fiction in daily health targets?

‘Five a day', reminders to move, more water, less screen time … maybe there’s a market for fitness trackers which detect the fact and fiction of health targets. Pictures: iStock

Do you worry if you fail to get eight hours of sleep a night? Always make time to brush your teeth twice a day? And if your Fitbit or Apple Watch tells you to move every hour or increase your daily steps, do you do it? We all think we know what our health targets should be, but are we right? Here the experts sort the facts from the fiction.

Eat 2000 calories a day

FALSE

For years the standard nutrition advice for those wishing to maintain a healthy weight and prevent ill health was a daily intake of 2,000 calories for women and 2,500 for men. But in recent years Public Health England has changed its guidelines to recommend 1,800 daily calories, consumed as 400 calories for breakfast, 600 calories at lunch and dinner, and 200 calories in snacks.

Why the lower target? Because left to our own devices, we eat a lot more than we think, which is one of the reasons nearly two thirds of UK adults (63 per cent) are classed as being obese or overweight.

Most people underestimate their calorie intake by 32 per cent, according to the Office for National Statistics.

We also over-estimate how much energy we expend, with a study showing that people typically over-estimate their physical activity levels by 36 to 173 per cent.

True: You need to move. Picture: Supplied

Exercise for 30 minutes a day

TRUE

Most of us know by now that government and World Health Organisation (WHO) guidelines state that adults need to do at least 30 minutes of moderate aerobic exercise a day to stay healthy — brisk walking, dancing, cycling, tennis and aerobics all count. We need to get our heart rate up every day, and countless studies support this amount as a daily minimum.

One recent study in the British Journal of Sports Medicine by scientists at Glasgow Caledonian University involved more than 130,000 adult participants, and its results confirmed that a daily half an hour of activity decreased the risk of early death by up to 80 per cent for most people.

Be warned, though, that if you spend 11 or more hours a day sitting, the same researchers suggested that you would need to do more than 30 minutes of daily exercise to offset the ill effects.

Eat five portions of fruit and vegetables a day

FALSE

This familiar target has been recommended since the government launched its “5 a day” campaign in 2003, based on the WHO’s recommended minimum daily intake of 400g of fruit and vegetables. Unfortunately we’re hopeless at hitting the target — the National Diet and Nutrition Survey in 2019 discovered that our average intake is a paltry 3.7 daily portions of fruit and veg – and scientists believe that we should double the recommended amount.

In a meta-analysis of 95 studies on fruit and vegetable intake by two million people, scientists from Imperial College London found that the greatest benefit to health came from eating 800g of fruit and vegetables a day, equivalent to ten portions (one portion is defined as 80g).

“Our results suggest that, although five portions of fruit and vegetables is good, ten a day is even better,” says Dr Dagfinn Aune, the lead author of the paper published in the International Journal of Epidemiology. However, the team did find that even a daily intake of 200g, or 2.5 servings, was associated with a 16 per cent reduced risk of heart disease, an 18 per cent reduced risk of stroke and a 13 per cent reduced risk of cardiovascular disease.

Stand up every hour

FALSE

Your fitness tracker might prompt you to stand up from your desk or sofa every hour, but is it enough to offset the ill effects of sitting, which include weight gain and rising blood fat and sugar levels? Probably not, say Swedish researchers, who recently reported in the American Journal of Physiology that getting up and moving about as much as possible — some study participants climbed stairs, marched on the spot or even performed squats — every 30 minutes for about three minutes is what is needed.

Erik Naslund, a professor in the department of clinical sciences at the Karolinska Institute in Stockholm who led the study, says his findings may represent “the minimum effective dose for breaking sedentary behaviour”. In other words, even more standing up could be more beneficial.

Drink eight glasses of water a day

FALSE

We take our bottles of water everywhere with us, but do we really need to? The idea of a daily water consumption target was challenged as long ago as 2011, when a report published in the British Medical Journal described the advice to drink six to eight glasses of water a day to prevent dehydration as “not only nonsense, but thoroughly debunked nonsense”.

Clinical guidelines produced by the European Food Safety Authority recommend that we drink 35ml of fluid per kilogram of our body weight every day, which for most people equates to 8-12 cups a day, or 2 litres for women and 2.5 litres for men. But that recommendation includes fluid from sources other than the tap.

Yes, you need to eat right. Picture: Supplied

In a trial by the universities of Stirling, Loughborough and Bangor, scientists testing the effects of 13 commonly consumed drinks on urine output and fluid balance found orange juice and milk to be more hydrating than plain water. “The human body isn’t fooled by the presence of other ingredients present,” the nutrition therapist Ian Marber says. “It doesn’t have to be plain water and it doesn’t have to be exactly eight glasses or more a day.”

If you eat fresh fruit and vegetables, soups, sauces or casseroles, they all contribute to your fluid intake.

Look away from your screen for 20 seconds every 20 minutes

TRUE

Screens are no worse for your vision than other “near” work, such as reading or intricate DIY, but they can still be harmful. Too much screen use, especially sitting in one position, can overwork the internal and external muscles of the eye, causing eye strain and fatigue.

David Cartwright, an optometrist and the chairman of the charity Eye Health UK, says that the 20-20-20 rule of shifting your gaze away from the screen every 20 minutes to look at something else 20ft away for at least 20 seconds is recommended. “Try to blink when you do this as blinking lubricates the eyes and reduces eye tiredness,” he says.

Take 10,000 steps a day

FALSE

Walking is good for our health, but how many daily steps we should aim for as a minimum is open to debate. It largely depends on your age and fitness level, as well as what you are hoping to gain from your daily steps.

Activity trackers may have it as their default goal, but in reality the mantra of doing 10,000 daily steps was devised randomly by the Japanese manufacturer of a pedometer in the 1960s and adopted purely for marketing reasons, with no scientific backing.

One new study of 2110 adults suggests that accumulating at least 7000 daily steps from the age of 40 can result in a 50 per cent lower risk of premature death. However, the study also found that people taking more than 10,000 steps a day rarely outlived those taking at least 7000. So while it’s not unhealthy to take more than 10,000 steps, it won’t necessarily lead to a longer life.

10,000 steps isn’t ‘one size fits all’. Picture: iStock

If your goal is to lose weight, however, it’s a different story. The consensus is that you need to cover closer to 15,000 steps a day, or about 11 kilometres. Researchers at the University of Warwick found that postal workers who covered this distance daily had normal body mass indexes, waistlines and metabolic profiles.

Eat fish twice a week

TRUE

The official recommendation from Public Health England is that we should consume two 140g portions of fish a week, including one of oily fish, but we fall well short, with an average weekly intake of only 54g.

All fish is a source of lean protein, vitamins A and D, B vitamins and minerals such as iron, iodine, selenium and zinc. In addition, oily, darker-fleshed fish, such as salmon and herring, are rich in heart-healthy omega-3 fatty acids. Note that tuna, either fresh or canned, doesn’t contain particularly high levels.

Juliette Kellow, a dietitian and spokeswoman for the British Dietetic Association, says that studies show that fish consumption is associated with lower incidence of heart disease, and omega-3 fatty acids are important for brain and eye health, but we should be more adventurous in what we choose.

“We tend to focus too heavily on cod, haddock, tuna, salmon or prawns,” Kellow says. “A greater variety of fish and from UK waters would be better for the environment and also meet dietary needs.”

If you don’t eat fish, you can obtain some omega-3 fats from seaweed, chia seeds and walnuts, as well as tofu and other soy products.

Brush your teeth twice a day

TRUE

Research suggests that, in theory, tooth brushing once a day should be enough to maintain oral health, remove plaque and prevent tooth decay, but unfortunately scientific literature also shows that few people brush well enough for that to be sufficient.

Twice a day is recommended by the National Health Service and the British Dental Association, but surveys by the Oral Health Foundation suggest that almost one in five adults don’t achieve that target. “The aim should be to brush well for two minutes twice a day using a fluoride-containing toothpaste,” says Dr Nigel Carter, the chief executive of the Oral Health Foundation.

The latest studies suggest that a three-minute daily goal is even better. Researchers at the Ewha Womans University College of Medicine in Seoul, South Korea, have reported that brushing teeth three or more times a day is associated with a lower risk of atrial fibrillation, heart failure, type 2 diabetes and strokes. Poor oral health increases the risk of bacterial infections in the bloodstream, which can affect the heart.

Get eight hours of sleep a night

FALSE

We all know that too little sleep can have far-reaching effects on anything from our memory to our waistline, but do we really need a full eight hours a night to be healthy? There is no one-size-fits-all when it comes to how much sleep we need, says Dr Neil Stanley, a sleep researcher and the author of How To Sleep Well. A lot depends on how we are hardwired biologically and on our body’s individual requirements.

Twice a day, every day. Picture: iStock

“It is disingenuous to suggest that eight hours’ sleep is anything other than an average figure for most people, and it should not be held up as an ideal,” Stanley says. “Generally the durations of sleep that are not recommended for adults are having less than six hours or more than ten hours, and most people do best having somewhere in between.”

Stanley says that the only reliable way to tell you are getting enough sleep is if you wake up feeling refreshed and ready to face the day on a regular basis.

Eat three meals a day

FALSE

Your mother may have insisted you eat three meals a day to remain healthy, but most scientists would now agree that this is not a blanket rule that suits everyone, particularly when it comes to weight maintenance. Some studies have shown that people given the same daily amount of food have healthier outcomes and lose more weight if they consume it as two meals instead of three.

In a meta-analysis of 22 clinical trials looking at the impact of meal frequency on 647 participants, published in the journal Advances in Nutrition, it was suggested that eating two meals a day slightly reduced body weight compared with three meals providing the same total calories, and that two daily meals were “probably” better than six smaller meals when it came to shrinking waist circumference. One daily meal – reportedly the practice of the model and actress Elizabeth Hurley, who has admitted that “the only meal I have is dinner” – was ranked top for reducing body weight.

Tim Spector, a professor of genetic epidemiology at King’s College London who has studied meal frequency and timings, says that not everyone benefits from the same approach.

“Our research shows that everything from our blood sugar to our gut microbiome responds differently to different foods,” he says. “Even our body clocks play a part in determining when is best to eat, and it’s because we all have a different circadian rhythm that some people thrive when they skip breakfast and others don’t.”

In general, though, the more you can spread out your meals the better, and whether you prefer two or three daily meals, try consuming them within an “eating window” of eight to ten hours to allow your body a period of fasting.

“Longer gaps between meals can improve your metabolism and potentially help with weight loss,” Spector says. “Experiment and find out what works for you.”

Get outside every day

TRUE

Direct sunlight is the most efficient source of vitamin D – it is synthesised when chemicals in the skin react to ultraviolet rays – and the government advises getting outside for 15 minutes daily between April and September, preferably between 11am and 3pm when sun is at its strongest, to boost your supplies.

But there are other reasons to get a dose of daylight, even in winter. David Ray, a professor of endocrinology at the University of Oxford, says we are not designed to be indoors all day and our body’s circadian rhythm has evolved to thrive in cycles of daylight and darkness.

“Even on cloudy, darker days it is important to get outside, preferably as early in the day as possible,” Ray says.

“No artificial light matches daylight when it comes to resetting our body clocks, and the earlier you do this in the day the better.”

Getting outside every day, even in moderate daylight, has also been shown to have a protective effect on the eyes, reducing the risk of developing short-sightedness (myopia) in children.

The Times