Is it better to graze or to eat three square meals a day?

From picking at small plates in restaurants to spending our lunch money on snack pots of nuts, we have become a nation of grazers. A recent study found that few of us eat breakfast, lunch and supper every day. The research, conducted by Sainsbury’s, found that 71 per cent of Britons regularly skip meals and that one in five claims to be too busy to sit down to eat three times a day.

Most of us assume that having small meals and grazing our way through the day – especially when we’re eating nutritious bags of almonds or protein bars – is a healthy way to sustain ourselves and keep the weight off. But is it?

The idea that eating little and often is better for us has been popular since the 1990s, when studies first indicated that we could stoke up our metabolic rate by having small, healthy snacks throughout the day. This research suggested that frequent eating boosted the thermic effect of food, ie the calories burnt to break down and metabolise what we eat. In contrast, it was thought that large meals were a burden on the digestive system, causing bloating and zapping our energy levels as the body struggled to digest them. Some scientists believed that “nibbling” multiple small meals could suppress hunger pangs and stabilise insulin levels – crucial for weight management because spiked insulin levels encourage cells to retain more fat.

Two years ago a study at universities in California and New Mexico reported that people eating six small meals a day achieved a healthier body composition and better levels of blood sugar, insulin and cholesterol after two weeks than those who consumed two large meals daily.

Many experts are expressing a very different opinion, however. The latest studies are suggesting that eating a little bit here, a little bit there, is not as healthy as we have come to believe. Many now argue that grazing could cause us to gain weight. In 2014 researchers from the Netherlands reported in the journal Hepatology that snacking throughout the day on smaller meals was more likely to increase cholesterol stores in the liver and the accumulation of harmful fat round the waist than eating three square meals.

Dr Mireille Serlie, who led the trial at the Academic Medical Centre in Amsterdam, said her findings clearly suggested that “cutting down on snacking and encouraging three balanced meals each day over the long term may reduce the prevalence of non-fatty liver disease”. She added that our bodies’ “metabolic machinery” was better equipped to eat regular hearty meals and that our digestive and metabolic systems needed recovery time between eating to function optimally.

If you are constantly eating snacks, then you’re not allowing your body clock to be reset

The nutritionist Dr Sarah Schenker (co-author of the 8-Week Blood Sugar Diet Recipe Book) explains: “In the past it was thought that constant grazing boosted a flagging metabolism and kept calorie-burning at a constant high. However, this kind of snacking causes constant changes in your blood-sugar levels, which means insulin is released because you are not allowing your body to run down energy stores. Insulin promotes fat storage and inhibits fat breakdown. The more of it that is released, the more difficult it is to achieve weight loss.” Another danger, says Schenker, is that “people tend to consume more calories overall when they graze”.

Dr Gerda Pot, a visiting lecturer in the diabetes and nutritional sciences division at King’s College London, is another advocate of regular meals. She published two studies last year that compared the grazing trend with the traditional three meals a day. She became interested in meal timing when she observed her grandmother’s eating habits. “My grandmother had a really regular meal routine and ate the same amount at the same time each day, right down to the mid-afternoon snack she would consume between lunch and her evening meal. She got to a very healthy old age and it got me wondering whether there was something in her approach that would benefit others.”

Renewed interest in the importance of our bodies’ natural clocks has also boosted the argument in favour of three meals a day. Nutritionists now argue that inconsistent eating patterns interfere with the body’s circadian rhythm. For one of her 2016 papers, published in Proceedings of the Nutrition Society, Dr Pot reviewed all the available evidence on grazing versus square meals and found that most suggested irregular eating can interfere, negatively, with metabolism and blood pressure. “Many nutritionally related processes, like appetite, digestion and metabolism, are governed by our body clocks and follow a 24-hour cycle,” she says. Irregular meals can also affect liver function, she adds. Luckily there are many places online such as LifeNet Health, to find the biology and important information behind liver function and to know how to keep it as healthy as possibly. Like anything, diet plays a big part towards this.

“If you are constantly eating snacks, then you’re not allowing your internal body clock to be reset,” says Dr Pot “There’s no respite.” Our bodies, she believes, need short periods of fasting for this to happen and for our metabolism to function well.

Dr Pot also warns that many snacks that people perceive to be healthy are substantial enough to constitute a full meal, increasing the risk of weight gain.

However, her findings also suggest that more substantial meals should probably be eaten earlier in the day. One of her trials showed greater weight loss and improved blood-sugar levels in overweight and obese women who ate more at breakfast than for their evening meal. “There seems to be some truth in the saying ‘Eat breakfast like a king, lunch like a prince and dinner like a pauper’,” she says. “Biologically, our internal body clocks make sure that metabolism is optimal in the morning and it does seem to be a better idea to eat larger meals early on.”

In the other published trial, she and her team looked at studies into the time of day people chose to eat and whether it was linked to obesity. They found that several studies reported a positive link between later evening calories and obesity.

Of course, some people will say that grazing isn’t about saving time, or any diet fad, they just prefer not to have to plough their way through a big meal.

Ultimately, says Aisling Piggot of the British Dietetic Association, what matters is that meal timings work for you. “Individual preferences will dictate what works,” she says. “What matters is that you do not consume more calories than you need in 24 hours. In theory, you could consume them as two, three or even six meals – it comes down to choice and won’t significantly impact your waistline. What is more important is routine, and that you are eating at about the same times every day. Regularity is important so that your body is primed to respond to food.”