There are so many different slimming diets and weight loss fads out there it can leave many people looking to lose a few pounds wondering just where to start. Intermittent fasting - an eating plan that switches between going without food for part of the day - is one of the latest crazes.
Celebrities and fitness gurus swear by the technique and, at least in this case, most health and fitness experts seem to agree it has some major benefits. As well as weight loss, they include sleeping better, improved concentration and even reversing type 2 diabetes.
While many diets focus on what to eat, intermittent fasting is about when you eat. But even then, there is a fair risk of confusion. Options include the 16/8 method (eating during an eight hour window each day), or the 14/10 and many other variations.
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It begs the question, when is the best time to eat during the day, to lose weight at least? Well, scientists in the USA may have the answer follow publication of the latest research.
They recommend you stop eating at 3pm every day to get the maxium weight loss benefits - and that includes going without snacks in the evening. The diatary experts analysed 250 studies in which participants fasted for at least 14 hours a day.
They found that the best method for losing weight was to limit your food intake to between the hours of 6am and 3pm on a daily basis. The review discovered that eating this way meant it was easier for blood sugar levels to stabilise and for people to shed stubborn fat around their hips and bellies.
This method, they found, ties in best with humans' natural body clock. It also turns out to be more in step with how our hunter gatherer ancestors would have eaten. Stopping eating at 3pm daily also had the greatest effect in terms of reducing inflammation, according to the report.
By eating earlier in the day, as opposed to later, also had the benefit of ensuring healthier bacteria in the gut. This is important because it helps the body's immune system and assists with fighting off illness and disease. The research was recently presented at the European Congress on Obesity.
One of the most respected researchers in the field of intemittent fasting is Dr Courtney Peterson, of the University of Alabama in the USA. She said: "Data suggests that eating earlier in the day improves weight loss, glycemic control, appetite, insulin resistance and fertility."
A similar study published in the Nature Communications journal supported this position. "Western-style diets, which include fat-rich food and snacks that are consumed around the clock, play a causative role in the development of some chronic diseases," it reports.
"In contrast, our human ancestors did not have continuous access to a food supply." Dr Peterson appears to debunk the eat a little and often advice. She said that snacking through the day actually increases the chances of obesity by a factor of 57 per cent.
She added that by eating earlier and sticking to regular mealtimes, slimmers can reduce what she describes as a "metabolic jetlag". Dr Peterson said: "Most people eat within a 12-hour window but that time window shifts from day to day.
"So for some people that eating window can be 14 or 15 hours because one day they'll eat breakfast and another day they'll eat really late. We think benefits come when it is the same eating time window each day.
"The reason for this is you have an internal biological clock, called the circadian system. This clock makes you better at doing different things at different times of the day."
Dr Peterson said this principle tied in with overall health and fitness. "So for instance, your best muscular strength, greatest reaction time and greatest coordination are in the afternoon," she said.
"Your highest alertness, testosterone production, and in most people best blood sugar control is in the morning. So your metabolism is kind of optimised. Your body is optimised to do different things at different times of the day. One of the things that's really important about having these optimal circadian rhythms is doing the same thing at a consistent time of day."
She added: 'A great example of this is say, you normally go to bed at 10pm and the next night you're out partying and go to bed at 2am. Even if you're in bed for those same eight hours of sleep, you feel way less good.
"That's because your body thinks it has shifted several time zones. You get this sort of feeling of jetlag. There's actually a similar thing going on when you shift your meals from day to day and we now call that metabolic jetlag."
