WHY WHEN YOU EAT MATTERS

Eating within a specific time window is fast becoming the hottest healthy eating trend. Is it a fad or a useful health fix? Nutritionist Anita Bean finds out…

Do meal times make a difference?

Most of us tend to eat pretty soon after we get up in the morning, snack throughout the day and continue grazing late into the evening. Whether it’s a few biscuits in front of the TV, a packet of crisps while driving or a late-night snack before bed, food is never far away, and we rarely take a break from eating. This means our eating ‘window’ often spans 14 hours or longer, but could this be putting our health at risk?

Researchers say that the problem with eating this way (even if you are within a healthy weight range) is that it disrupts the body’s 24-hour cycle, known as the circadian rhythm (or body clock). This governs the sleep-wake pattern, the digestive system and every cell in the body. It means that your body is pre-programmed to sleep, eat and do certain things at certain times of the day. For example, the gut is better at digesting and absorbing food during the day than at night, because it’s primed to repair itself during this time and so the production of saliva and digestive enzymes slow down and food moves more slowly down the digestive tract. If you eat late at night, food sits there.

‘Eating late at night is out of sync with your circadian rhythm and means that the body doesn’t get a chance to fully carry

out the natural repair processes in the liver, gut and other organs,’ says research dietitian Dr Rona Antoni. ‘All this puts us at bigger risk of obesity and chronic diseases, such as type 2 diabetes, hypertension and heart disease.’ Researchers have now come up with a solution that can restore your circadian rhythm, boost your overall health and help you lose weight (if you need to), yet it doesn’t involve dieting or changing what you eat. It’s called time-restricted eating, and it involves consuming food within a window of 12 hours or less; a much smaller time frame than many people are used to. This effectively extends the period overnight when you are ‘fasting’, or not eating. For example, you can choose to eat between 7am and 7pm or 8am and 8pm. Thankfully, the term ‘time-restricted eating’ isn’t as prohibitive as it sounds. You are controlling when you eat, not what you eat. You are not required to deliberately restrict your typical food intake, so it’s not another diet trend; it’s a pattern of eating. This makes it eminently doable, regardless of your lifestyle or food preferences. It’s also a way of eating that sits comfortably with the goals of self-compassion, confidence in the way you look and appreciating all the incredible things that your body is capable of doing.

What are the health benefits?

While time-restricted eating is not specifically a weight-loss diet, many people find they lose body fat. ‘When people reduce their eating window to less than 12 hours, they tend to “accidentally” reduce their calorie intake and lose weight,’ says Dr Antoni. ‘This happens either because they feel less hungry, or have fewer opportunities to eat, particularly in the evening when people tend to graze.’

Time-restricted eating has only been tested in a handful of studies to date, but researchers at the Salk Research Institute for Biological Studies in California found that when people were instructed to cut their eating window from 14 hours to between 10 and 11 hours, they lost an average of 3kg over 16 weeks without counting calories or changing what they ate. People who took part in the study also reported that they felt less hungry, more energetic and slept better.

A study by the University of Illinois at Chicago revealed similar results when people reduced their eating window to just eight hours. However, there were no further weight-loss benefits.

A simple way to adopt time-restricted eating is to delay your usual breakfast time by 90 minutes and bring your usual dinner time forward by 90 minutes. In Dr Antoni’s pilot study at the University of Surrey, people who did so lost a higher amount of body fat after 10 weeks and saw a more beneficial effect on their blood sugar levels compared with those following whatever schedule they liked.

THE ADDED IMPACT

Eating within a 12-hour window may also have a positive effect on metabolism, subsequently lowering the risk of type 2 diabetes and cardiovascular disease. ‘The timing of when we eat has been shown to have a significant impact on our blood sugar, cholesterol ratios and the overall impact on our heart health,’ says Dr Rupy Aujla, author of The Doctor’s Kitchen: Eat To Beat Illness. ‘This practice of defining periods of eating to a rough 10- to 12-hour window has been shown to have favourable effects on markers of disease risk.’

Scientists from the University of Alabama had participants eat a very early dinner and not eat again until breakfast the next morning, and reported that it decreased their daily swings in hunger as well as reduced their blood pressure and risk of developing type 2 diabetes.

Why it works

The health benefits are believed to be the result of the extended overnight fast. This allows your body to ‘rest’, giving it time to switch its priorities away from digestion to ‘housekeeping’, allowing it to focus on repair, a process that includes killing off old cells and regenerating new ones. This maintenance may be the key to helping prevent type 2 diabetes and heart disease.

‘As a general rule of thumb, this practice allows cells of your liver, pancreas and gut to cope better with the food you ingest, so that it is less likely to cause blood sugar spikes and cholesterol imbalances, which can affect your heart health,’ says Dr Aujla.

How to begin

•Try having a later breakfast or an earlier dinner whenever possible. Every time you have a longer fasting period or avoid a late-night meal, you’re helping your health.

• Start fasting gradually by giving yourself an extended eating window of, say, 7.30am to 9pm; reduce this by 30 minutes every three days to reach a 12-hour period.

• Pick a window of time that suits

you, perhaps between 8am and 8pm, then commit to not eating or drinking anything that contains calories outside this period (water, calorie-free drinks, herbal tea and coffee and tea without milk or sugar are permitted).

• Eat a healthy, balanced diet and remember that this plan is not a licence to eat whatever you want. There’s no calorie counting, but focus on nutrient-packed, Mediterranean-style meals and whole foods: fruit, vegetables, beans, wholegrains, lentils, fish, olive oil and nuts.

• You don’t need to stick to a rigid 12-hour regime every day to reap the benefits. Practising this schedule five out of seven days a week is just as effective.