Two hot new regimes have caught on since New Year, each promising pain-free weight loss. Can either make the pounds melt away? Kate Hilpern gives the low-down
The Alkaline Diet - What do the experts say?
"The theory of the alkaline diet is that eating certain foods can help maintain the body's ideal pH balance to improve overall health. But the body maintains its pH balance regardless of diet," says British Dietetic Association spokesperson, Rick Miller.
What's more, while there is evidence that alkaline diets may help prevent the formation of calcium kidney stones, osteoporosis, and age-related muscle wasting, there isn't any proof that an acid-producing diet is the foundation of chronic illness.
Mind you, says Miller, you're unlikely to do yourself any harm. "The diet's premise is to increase alkalizing foods (such as fruit and vegetables) and reduce your intake of acid foods (such as meat, salt, and refined grains). Well, that's pretty much what we consider as healthy eating anyway and if you're overweight, of course it will probably help you shift some pounds.
The 5:2 Diet - What do the experts say?
Despite the claims that it helps people lose weight, increases their lifespans, improves cognitive function and protects against conditions such as dementia and Alzheimer's, the general medical consensus is that there isn't actually any firm evidence.
"Yes, there's some work on the effects of intermittent fasting on ageing and cognitive decline, but almost all these studies involve rodents, not humans, and the work on preventing diseases took place in laboratory conditions, with no guarantee of successful real-world outcomes," says British Dietetic Association spokesperson, Rick Miller.
He warns that if you're only eating a quarter of the calories you need, you may suffer low blood-sugar, as well as digestive problems, and that unless dieters increase their water consumption on their restricted days, they could suffer from constipation.
"I used to eat like the 5:2 diet in my teens and early 20s and it was called bulimia," says Zoë Harcombe, author of The Obesity Epidemic book, who is concerned that this diet carries a huge risk of encouraging disordered eating in people who are prone to it.
Sarah Schenker, spokesperson for the Nutrition Society, agrees: "The reality is that the 5:2 diet is how a lot of people manage their weight naturally. You eat all you want on the weekend, then have a day or two when you cut right down – and it does work for people. Also, there's something to be said for giving our systems a rest, particularly if we eat a lot of sugar and carbohydrates. So I don't think it's a fad and I'm certainly not dismissive, although I think we need to do more research."
Some experts believe that on the eating days, there's a risk of over-indulging and putting on weight, although a study by the University of Illinois found that people only eat about 100-110 per cent of the calories they needed. It's quite hard to fully make up for the lack of food on the restricted days.
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Source: The Independent