Anything relating to Jennifer Aniston's style, be it hair, life or wardrobe-related, peaks the public's interest, with fans forever wanting to know the 'secrets' behind her look. So when she recently revealed she fasts between meals, it made the headlines.
After rising around 9am, she said she then has a green juice and works out before having a cup of coffee. “Today, I woke up and had a celery juice,” she said. “Then I started to brew some coffee, but I don’t drink coffee that early.”
'Intermittent fasting' relates to any regime that incorporates a longer than normal fast period into your lifestyle. Registered nutritionist Claire Baseley tells Bazaar, "You might ordinarily finish your evening meal at 8pm and eat breakfast at 8am, so habitually you’d be fasting for 12 hours anyway. A '16:8' fasting plan would typically mean that you’d either skip breakfast or your evening meal so, for example, you’d finish your eating at 8pm as usual but then you wouldn’t eat again until 12 noon the following day. You would therefore be restricting your eating window to eight hours rather than 12 hours a day." Similarly, you could have your dinner at 6pm and your breakfast at 10am, which is an option for those who'd rather not skip an entire meal.
Other ways to fast include the '5:2', and 'day on, day off' diets, in which you fast for a whole day, two days a week or every other day.
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The benefits of intermittent fasting
Indeed, as Aniston notes she sees "a big difference" from fasting, for the purposes of weight loss, these type of diets can be successful "as they effectively mean you are consuming fewer calories by eating for less time," says Baseley. "As long as you don’t go crazy during the eating windows – it is still important, if not more so, to eat healthy, nutrient-dense foods because you’ve less time and eating occasions to consume all the nutrients you need to stay healthy, like fibre, protein, vitamins and minerals," she explains. Essentially, as long as you consume fewer calories than you burn, you will lose weight (which is only healthy if that is necessary, of course).
Some studies suggest that intermittent fasting can also have wider health benefits, Baseley also reveals, "such as improving blood lipid profile, lowering blood pressure, reducing cardiovascular and cancer risk and improving appetite control". However, she says that the majority of studies have so far been conducted in animals and more research in humans is needed before these findings can be confirmed. "It’s also worth noting that weight loss, if you have a high body fat percentage, can also bring about many of these improvements."
The drawbacks of intermittent fasting
Baseley explains that you are likely to feel hungry, low in energy, lightheaded and potentially grumpy when fasting. "It may affect your concentration levels and, on fast days or if you get active within a fasting window, you may feel like your performance is compromised when you exercise."
She notes that it’s also culturally and socially challenging, "and may be isolating, particularly if it means you miss seeing friends or family because you are fasting".
Is intermittent fasting right for you?
If you are someone who has a poor relationship with food or a history of disordered eating, these regimes are something to be avoided as they can worsen your relationship with food, Baseley points out. Also, if you have problems with digestion or absorption of nutrients, intermittent fasting is not advisable.
If the above doesn't apply, it still might not be right for you if you're not naturally organised when it comes to food. "If you don’t plan your eating well to ensure you are getting a balance of nutrients, plenty of vegetables and enough fluids, you may find yourself deficient in certain nutrients in the long term, or dehydrated - as much of our fluid comes from food as well as drinks."
Like any diet, therefore, intermittent fasting takes a lot of planning.
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How to fast safely
If you think it sounds suitable for you, to safely try intermittent fasting, pick a fasting window that works for your lifestyle. "If, for example, you don’t naturally feel hungry in the mornings, you may find a '16/8' regime works for you. If you have days at work or socially where it would be hard to fast for a period every day, a '5:2' plan might work better as long as you can plan the fast days around your schedule."
Of course, Baseley reminds us to make sure that while you are fasting, you stay well hydrated and during your eating windows that you eat a healthy, balanced diet. "Try to ensure you still eat five portions of fruit or vegetables each day (or as much as you can in your eating windows), along with whole grains, pulses, nuts or seeds and eat protein foods (like meat, fish, eggs, pulses, soy products for example) frequently." She says that this will help ensure that you maintain lean muscle as you lose body fat and also that you consume a wide variety of nutrients.
It’s still advisable to lead an active lifestyle, "so try to plan activity for the times when you are best fuelled," she says - such as late afternoon or evening on a '16/8' plan where you skip breakfast, or on non-fast days with a '5:2' strategy. "You can still train fasted, if you are used to doing so, but it will need to be at a lower intensity and you may find your performance is compromised."
If you are in any doubt, do speak with your doctor, a registered nutritionist or dietitian.
From Harper's Bazaar U.K.