The Ice Diet

How often have you started a diet at the beginning of the week, only to find your good intentions dwindling dramatically? Common excuses for falling off the weight-loss wagon are that people get too hungry. Or just bored.

It’s a familiar scenario that scientists say can be avoided by following a cutting-edge routine. You won’t feel tetchy, tired or hungry.

As a health writer, I have scrutinised diets for over two decades, only to find there is often little substance to the diet claims. But backing for the approach in my new book, The Ice Diet, is convincing. And it works.

Researchers at the Salk Institute for Biological Studies in California recently became the latest to prove that the daily mini-fast is the most effective way to shed pounds. Permanently. In a study published in the journal Cell Metabolism, laboratory mice were fed one of the following diets: high-fat, high-fructose, high-fat and high-sucrose or ordinary mouse food. Some of the mice were allowed to eat whenever they wanted; others had their food limited to feeding periods of nine, 12 or 15 hours. All mice had the same overall number of calories although some were occasionally allowed to ‘cheat’ by eating more at weekends.

At the end of the 38-week trial, the ‘nosh around the clock’ mice were generally obese and had developed other risk factors for heart disease. But the mice restricted to a nine- or 12-hour ‘eating window’ maintained a healthy weight, even at times when they fell off the wagon at weekends. When the other mice were switched to this daily regimen, they started to shed weight.

‘Time-restricted eating didn’t just prevent but also reversed obesity,’ says Professor Satchidananda Panda, who oversaw the studies. And the same approach works for humans.

Its appeal is simple. For starters, it is manageable. Time-tabling in chunks of the day when food is not consumed is incredibly easy to adopt. No foods (other than the blatantly unhealthy) have to be restricted and there’s no need for torturous calorie-counting, as long as it’s within prescribed limits. Snacking is not allowed, but the nutrient-packed and filling two to three daily meals recommended mean that you will rarely think about raiding the biscuit tin. The beauty of it is you can schedule meals to suit whatever you have planned; it works to your own routine.

While no ingredient is banned on the Ice Diet, certain foods are included because they accelerate fat-burning. Peppers (the hotter the better) have a powerful effect on metabolism by firing up calorie-burning good fat. Likewise, a compound called ursolic acid that’s found in many fruits, vegetables and herbs – including prunes, cranberries, bilberries, basil, thyme and apples (the richest source) – can also sharpen your body’s fat-burning capacity. Processed foods are, unsurprisingly, avoided on the Ice Diet. Last year, eminent cardiologists at Boston University School of Medicine said sugar and bad fat triggered a ‘death spiral for good fat’ after finding that they converted calorie-gobbling brown fat into the blobby white stuff that clings to our thighs.

Cool foods can also be helpful. Jennifer Lopez is among the celebrities who claims she drinks ice-cold water to aid weight loss. And emerging science suggests she might be on to something. In 2010, Dr Brian Weiner, an American gastroenterologist, published theories of how ice-cold foods might boost metabolism in the Annals of Internal Medicine. Dr Weiner’s theory is that anything eaten when partially or completely frozen uses up extra calories (he calls them Icals) to bring it to body temperature before it’s digested. Consume one litre of crushed ice daily, in the form of fruit-based frappucinos or low-sugar slush drinks, and your body burns an additional 160 calories, the energy equivalent of a yoga session or power walking 1.5km. ‘It doesn’t sound much, but over a year that equates to an overall loss of 10-12 pounds [4.5kg-5.4kg] of fat,’ he explains.

Weiner made his initial discovery when he switched from daily ice cream (his own dietary weakness) to ice-based sorbets. And lost weight. ‘I’m not suggesting that people eat only ice and ice-based products, but that some ice and cold food consumption is a highly effective adjunct to exercise and a healthy diet,’ he says.

He’s not the only medical expert to be intrigued. At the University of Nottingham’s medical centre, Professor Michael Symonds is looking at the way ice creams and lollies might boost metabolism by activating good body fat. Using thermal imaging cameras they have shown that eating ice cream immediately triggers good-fat activity in the neck area of a group of healthy students, suggesting the dessert activates calorie burning, at least temporarily.

Include as many of the metabolism-boosting foods as you can. And then watch the fat melt away...

1 Ideally eat two substantial meals a day – three if you are very active, but certainly no more than that, with no snacks in between. Don’t worry, portions can be quite generous.

2 Start with a 12: 12 eating window (that is, a 12-hour eating and a 12-hour fasting period) and see how you go for at least two weeks. Then try to extend the fasting period by no more than an hour a week with the aim of cutting your eating window to around 10 hours.

3 Don’t be swayed by commonly held beliefs that one meal is more important than another in terms of nutrition. We used to be told breakfast was of prime importance, but that is now disputed by leading scientists and studies published in the American Journal of Clinical Nutrition. Choose when you want to eat your meals and vary according to your needs.

4 Eat no snacks. Science has changed its mind about multiple small snacks being the favourable option for shedding weight. Indeed, a study at Purdue University found overweight people on diets felt more satisfied and less hungry when they ate three times a day compared to when they had six smaller meals.

5 Flavour food with spices and chilli when you can – they can stimulate the appetite and the activity of ‘good’ brown fat in the body; the type that burns calories.

6 Select cold desserts such as ice cream, slushy ice drinks, ice-cold beverages and sorbets.

The Ice Diet by Peta Bee is published by Penguin