Who What Why Can foods have negative calories

Dieters looking for a quick fix may turn to the promise of negative-calorie foods. But can eating actually burn calories?

Spring can be a confusing time for the body-conscious - a time when thoughts drift towards summer on the beach, but chilly temperatures have many reaching for an extra biscuit.

Those looking to shed a few pounds have often clung to the hope of "negative-calorie" foods - a workout for your taste buds that burns calories while you chew.

But do these foods actually exist?

"A negative-calorie food would by definition consume more calories, for the body to handle it and process it, than is contained in the nutrient content in the food.

"Theoretically thats possible," says Tim Garvey, chair of the department of nutrition sciences at the University of Alabama, Birmingham.

"In actuality there are no negative-calorie foods," he says.

Or, as the esteemed nutritionist Marion Nestle put it in a one-line email to the BBC: "Total myth. Nothing else to be said."

Consider celery, often proposed as a negative-calorie food due to its low-calorie count, high water density, and impressive fibre content.

While all that chewing and digesting of the fibrous food does burn calories, it doesnt burn a lot. "

There may be just 10 calories in a larger stick, but the body takes only one-fifth that much," to process, says Dr Garvey. "Its still calorie plus."

Never mind that man cannot live on celery alone, and few people just eat raw celery.

"Its more of a gateway to cream cheese or peanut butter," says David Grotto, a nutritionist and author of The Best Things You Can Eat.

Thats not to say that celery sticks - along with other high fibre, water-heavy fruits and vegetables - have no value as weight-loss aids.

"These foods do fill up the stomach and increase satiety," says Dr Garvey, keeping you from ingesting more calories later - but not burning off the calories youve already consumed.

But there are other things you can eat or drink that are supposed to work in a different way, by making the body work harder.

One is cold water, which the body has to warm up to 37C (98.6F). But Grotto is not particularly impressed.

"Theres no research to say that cold water drinkers burn more calories," he says.

"Any amount of metabolic hit is not a significant amount - maybe five calories."

Other foods have different ways of increasing the rate at which we burn calories (otherwise known as the metabolic rate). Caffeine, guanine, taurine and green tea extracts all have these properties, says Ron Mendel, who has done research on diet drinks that combine these ingredients.

In a study with only 20 participants, he found that those who consumed a diet drink called Celsius, which debuted in 2005, burned more calories than when they drank diet cola.

"The big picture here is, this is certainly not adding up to hundreds of calories a day by any stretch," says Mendel, the programme director for exercise science at Mount Union University in Alliance, Ohio.

"Theres no magic bullet," he says.

Still, he speculates the small gains could result in a loss of 10lb (4.5kg) over a year.

"I wouldnt say it was going to replace me exercising and make up for me from eating 4-5 donuts a day," he says.

"But if you just make that one change, over a significant amount of time, it could add up to something."

Dr Garvey is sceptical that the change in metabolism could lead to real weight loss.

As a doctor focused on obesity and nutrition, Dr Garvey maintains that the only real way to lose weight is the boring, old-fashioned, unsatisfying and ultimately successful method: eat fewer calories than you burn through exercise - not digestion.

By Kate Dailey

Source: http://www.bbc.co.uk/news/magazine-21723312

My stomach is so small I hardly have any appetite I cant keep weight on and I hallucinate Philip Schofield tells of dramatic effects of 5 2 diet

• Phillip, 52, said he was feeling porky so started the 5:2

• Has dropped from 12 and a half stone to 11 stone in ten months

• Suffered hallucinations as a result of 5.2. diet

• People were asking him if he was alright

• Gwyneth Paltrow has also suffered hallucinations when dieting

Phillip Schofield has revealed  he experienced hallucinations after losing weight on the 5:2 diet.

The presenter of ITV’s This Morning says the strict regime enabled him to shed one and a half stone. He now weighs a trim 11 stone.

But he said that there were side effects, having previously said he was struggling to adapt to the regime.

It allows men to consume only 600 calories two days a week while eating  normally on other days. Schofield,  52, confessed on Alan Carr’s Chatty Man show on Channel 4: ‘I have had hallucinations.’

The presenter said he went on a  diet after he thought he looked ‘a bit porky’ in a picture. ‘I wanted to be 11 stone,’ he said.

‘It took nine or ten months and now I am. My stomach is now so small I have hardly any appetite and can’t keep weight on.’

The 5:2 diet involves limiting yourself to 500 calories a day (600 for men) for two non-consecutive days per week and eating whatever you like for the rest, and has been the years most popular way of slimming down fast.

It was the brainchild of Mimi Spencer and Michael Mosley and has attracted celebrity fans including Benedict Cumberbatch and Miranda Kerr - and it prided itself on helping people lose weight all while improving blood pressure, cholesterol levels and insulin sensitivity.

Audience members were taken aback by his slim frame with one telling The Sun: His legs looked scarily thin. He didnt look right and people were saying he had lost too much weight.

Phillip isnt the only star to have suffered hallucinations as the result of a strict diet. Gwyneth Paltrow says she too was left hallucinating after a 10-day cleanse.

The Iron Man 3 actress is known for being active and eating healthy, but admits she has tried fads like juice cleanses in the past which did her more harm than good.

She explained: Ive done juice cleanses in the past, and in my twenties I did the Master Cleanse, which left me hallucinating after 10 days.

Be aware: a juice detox can crash your metabolism and lead to future weight gain, she wrote in The Telegraph.

Katy Mason, Nutritionist at NutriCentre.com, said: Anxiety, blackouts (memory time loss), difficulty concentrating and hallucinations can have many different causes, and so it is always important to get such symptoms checked out by your doctor. 

However, in this case, Phillip Schofields hallucinations would most likely be caused by low blood sugar levels from not eating enough.

If he had not slept well the night before, had a late night, been drinking alcohol, consumed a lot of caffeine, was stressed or had recently exercised then the situation could be exasperated as these things can contribute to low blood sugar levels. 

When on the 5:2, its really important to make sure you eat sensibly on the low calorie days, making sure your meal has a good ratio of protein to slow releasing carbohydrates.

PROS AND CONS OF THE 5.2 DIET

British Dietetic Association spokesperson, Priya Tew, shared her views....

Pros:
1. The 5:2 diet works as the 2 days of eating 500kcals mean that overall you eat less calories. Eating less calories obviously favours weight loss. 
2. There is some evidence showing that this style of diet can work but it is only a couple of studies and it is not long term evidence. Most people want the weight to come off and stay off for good. We dont know the long-term effects of the 5:2 diet yet.
3. Intermittent fasting may help improve insulin sensitivity although more research is needed to back this up.
4. Fasting can lead to you being more in touch with your hunger cues and responding to them more appropriately.

Cons:
1. The fasting days can lead to lower energy, poor mood and concentration and a preoccupation with food as well as problems sleeping on fast nights. So you end up not able to eat much but constantly wanting to and being grumpy and tired about it! Exercising on these fasting days can be very difficult.
2. You can eat a completely unbalanced diet and end up with a poor nutritional intake as this diet focuses on calories and not getting the right nutrition and balance. In the long-term, eating an unbalanced diet can increase the health risks of chronic disease. For example focusing on eating 5 or more portion of fruit and vegetables, including wholegrains in your diet and having 3 portions of calcium foods per day are important nutritionally but are not considered in an intermittent fasting diet.
3. Although the 5:2 diet is meant to be a long-term solution, for most people it isnt a sustainable way to eat and it takes a lot of discipline. For long term weight loss, long-term lifestyle changes are needed. The risk with this diet is that people lose the weight, then find they cannot stick to the fasting principles and put it all back on again. Yo-yo dieting has been shown to be detrimental and can lead to the weight creeping up over the years.

Source: http://www.dailymail.co.uk/femail/article-2657151/My-stomach-small-I-hardly-appetite-I-weight-I-hallucinate-Philip-Schofield-tells-dramatic-effects-5-2-diet.html