Intermittent fasting is a proven way of losing weight quickly – but it may not work for everyone

Many religions have for centuries adopted the spiritual practice of intermittent fasting, promoted as a path to enlightenment. During Ramadan, the ninth month of the Islamic lunar calendar, observant Muslims eat only before dawn and after sunset for 30 days.

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In recent times, fasting has experienced a comeback as a means to lose weight. Advocates tout intermittent fasting as a way to better health: it may help shed pounds, build muscle, lower your risk of diabetes and cardiovascular disease and even extend your life.

Intermittent fasting typically involves intentionally avoiding or drastically restricting calories on one or two days a week while eating normally on other days. For many people, a diet that includes a small amount of food, even on fasting days, may be easier to follow than a true fast.

Different fasting regimens include:

* Alternate-day fasting, such as the Eat Stop Eat programme, requires alternating days of consuming foods or drinks that have no calories with days spent eating and drinking normally.

* Modified fasting regimens, such as the 5:2 or 4:3, involve eating only 20 to 25 per cent of one’s usual needs for two or three non-consecutive days a week – and eating the usual daily requirements on the other five or four days.

* Time-restricted fasting, such as Lean Gains, allows for the consumption of food and drinks within specific time windows throughout the day, which induces fasting periods on a routine basis.

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Some find alternate-day fasting easier than cutting calories each day because there are fewer days when self-discipline is needed. Some people can get through a fasting day knowing that on feed days they will feel recharged again. With reduced-calorie diets, they tend to be hungry all the time. Fasting offers another option for people caught in the yo-yo diet cycle. They are relieved of the stress of having to figure out what to eat – and not to.

To help build muscle and achieve his weight goal, personal trainer Wesley Lee took up intermittent fasting eight months ago.

“I have regenerated my body to its true function, lost weight, boosted my brain health and improved my physical performance,” Lee says. He is able to lift heavier weights and perform more reps. He has increased his ability to focus and his mental stamina to tackle work and life issues.

He adopts the “5:2 diet”. On his two fasting days, also his rest days, he eats about a quarter of what he would eat in a typical day, around 750 calories, consisting mostly of fresh greens, a protein-enriched smoothie or green juice, and a cup of drip-brewed coffee.

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He has shed about 10 kilograms.

The key is not to overeat on “feed” days, but to choose nutrient-dense foods to get enough energy to support health and daily activities.

While Lee is comfortable with intermittent fasting, it may not be for everyone.

Recent studies suggest that intermittent fasting may be an effective alternative strategy for weight loss, especially for overweight and obese adults.

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A review study in the United Kingdom published in the The Journal of Federation of American Societies for Experimental Biology in 2015 found that people on such diets lost about nine per cent of their body weight over six months, about the same amount of weight loss seen in studies of traditional dieting. A key difference, though is that about 80 per cent of the subjects in the fasting studies were able to keep to the diet, while most traditional dieters fell off the wagon.

The diets in these studies involved drastically cutting calories on fasting days, though it is possible to shed weight on a less restrictive fasting-day diet. Those who want to give intermittent fasting a try could consider fasting in the evenings twice a week – skipping dinner, or having a serving of yogurt or fruit. This restricts them to about two-thirds of their usual calorie intake on fasting days, or about 1,300 calories instead of their typical 2,000.

A recent study from the University of Southern California on more than 70 people found that intermittent fasting reduced cardiovascular risk factors, waistlines, and total body fat. However, the longer-term benefit or harm from fasting among people who are overweight or obese, and particularly among people of normal weight, is unknown. More studies have been done on rodents than on people.

As an alternative to fasting for health or weight loss, try these tips:

1. Eat and drink less in the evening

The old saying “Breakfast like a king, lunch like a prince, and dine like a pauper,” might prove to be healthy advice. The human body functions differently during the day than at night. Processes such as digestion slow when it is dark and/or cold outside and speed up when it is brighter and warmer. Both human and animal studies have shown that eating in accordance with our body’s internal clock may be a better weight-loss approach.

2. Eat smaller, frequent meals

Some people find they get hungry frequently or struggle with blood-sugar crashes during the day. If they are fasting, they may binge on feeding days. A more practical and sustainable option is to have more than three meals a day – but to keep them light.

3. Limit eating time

If severe calorie restriction is not for you, another option is to limit the period of time in which you dine each day, say from 9am to 5pm. This allows more time for the body’s hormones to return to baseline levels without disruption. A regime that regularly limits calorie intake this way will likely support weight loss.

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The key is to find a diet regime that is nutritionally sound and can be incorporated into your lifestyle without feelings of deprivation and other negative effects. Making lifelong, well-balanced dietary choices will help you get needed nutrients and maintain a healthy weight.