For years we’ve been advised not to shed the kilos too quickly and told the answer to long-lasting leanness is to lose weight slowly and sensibly. However, new research suggests the hard-and-fast approach has its place for people whose lives are at risk due to their weight.
Experts now say that if you’re obese or seriously overweight, the best way to budge the bulge is fast and furiously, dropping up to 2kg a week, as you’ll be more likely to achieve your goal than those doing it slowly and steadily. And the old adage that the faster you lose it, the faster you regain it, has also been shown to be a myth. That’s the finding of dietitian and University of Melbourne researcher Katrina Purcell, co-author of a recent study into rapid weight loss.
“At university, the message given to us was to promote gradual weight loss because that was the best way to lose weight and keep it off,” she says. “That’s not the message I give out anymore.”
Purcell says the most significant discovery in her research, which was undertaken with Melbourne’s Austin Health weight control clinic, was unexpected: more than 80 per cent of dieters on the rapid program lost 12.5 per cent or more of their weight, but only half of those on the gradual one did.
How rapid weight loss works
Another supporter of the rapid weight loss approach is associate professor Amanda Salis of the University of Sydney’s Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders, who’s researching how it works.
She believes that a moderate and measured approach to dieting can cause physical hardship for dieters, which can vastly increase the likelihood that the diet will fail.
“A number-one reason for diet failure is what I call the ‘famine reaction’, when the body responds to being on a restricted diet by increasing appetite, inducing lethargy and slowing down the metabolic rate,” Salis says.
“These responses make it much more difficult for a person to stay on a weight-reducing diet, encouraging them to not only come off the diet but also to return to the old eating habits that made them gain weight in the first place.”
This is where the benefits of the rapid weight-loss method kick in, Purcell says, explaining that after about three or four days on a “very low energy diet” (VLED), ketosis (when the body breaks down fat to form ketones as an alternative fuel source to glucose) can set in, and it “just gets easier”.
When Purcell talks about “very low energy”, she means it – the diet she recommends is 800 calories (3300kJ) a day, or about three quality meal replacement shakes with a handful of green vegies for something to chew on. To put that into perspective, the worldwide recommendation for women wanting to lose weight is 1200 calories a day.
The length of time you need to stay on a VLED for depends on your starting weight and how much you want to lose. Salis gives the example of a sedentary 50-year-old woman of 77kg and 160cm tall, who’s classified as obese: “Before the diet, she’d need about 2055 calories (8600kJ) a day. To reach her target weight of 62kg, she’d go on a VLED of 800 calories (3300kJ) a day for 12-16 weeks. After the diet, she’d only need 1750-1890 calories (7300-7900kJ) a day, due to her smaller body size and the effect of the diet on her metabolism.”
Salis says VLEDs are typically used in clinical practice for 8-16 weeks, but there are case studies of people using them under clinical supervision for up to 12 months.
Not for everyone
The “all or nothing” aspect of this diet is the key to its success, Salis says, explaining that you can’t take a break on weekends because theketones won’t get to work to their full appetite-suppressing effect.
It’s also not for everyone and shouldn’t be abused by those who don’t need it. “This diet is designed for people who are obese or are overweight and have a high risk of metabolic diseases, and must be done under the supervision of a health professional who can also help with weight maintenance when the famine reaction kicks in at the end of the diet,” Salis says.
Keeping the weight off
The ugly truth is that neither the gradual nor rapid method stops dieters from regaining weight. Purcell’s study followed 102 people on a rapid diet and 102 on a gradual diet, all with a BMI of 30 (obese) and found that regardless of the method, they regained about 71 per cent of the weight they’d lost three years after they dieted.
She admits that the secret to losing weight and keeping it off is yet to be truly discovered, at least in a scientifically proven way.
To that end, Purcell tells obese and overweight people who seek her help “to go on a very low energy diet, using approved meal replacements, until they reach their target weight – so, yes, the rapid program. Then every couple of months, when they notice a kilo or two come back, they go back on to that diet for a week or two to return to their goal weight. And they need to do this for the rest of their life.”
A typical day on a rapid weight-loss diet, according to Salis
- 3-5 very low-energy diet products, such as shakes, soups or bars (only use "total meal replacement" products)
- 1 tsp oil
- 2 cups non-starchy vegetables
- 2 L water (at least)
Warning: This diet is only suitable for certain people and shouldn't be carried out without medical supervision
What other health experts say
Nutritionist Teresa Boyce
“Muscle loss and nutritional deficiencies can occur if it’s done for too long”
“[The merits of a rapid weight-loss diet] depend on how low the calories are and also on the length of time that the person is on a strict low-calorie diet.
It can be really motivating for very overweight individuals to see a big shift with weight loss, however, with severe calorie restriction over an extended period of time you may see a reduction in not only fat but also muscle mass, which ultimately leads to long-term weight gain. With severe calorie restriction you can also see nutritional deficiencies.
A short-term calorie restriction diet is generally OK as long as you educate the individual on a long-term approach to healthy, portion-controlled, real food meals, because there’s no point restricting calories and dropping weight if you don’t know how to nourish [your body] and maintain [your weight in the] long term.”
Psychologist Leanne Hall
“It’s a band-aid solution if you don’t address the emotional issues”
“The issue is why the weight went on in the first place. Most, if not all, obese people have a poor relationship with their body and food.
In these cases, weight gain is a consequence of multiple psychological factors: bingeing, poor impulse control, low self-esteem (even depression), using food to deal with emotions. While these people may be able to lose weight rapidly under prescriptive conditions, the issues that triggered the weight gain in the first place remain.
Up to 95 per cent of people who lose weight through diets regain that weight within five years because they’re trying to adhere to an overly restrictive diet based on deprivation.
Rapid weight loss is a band-aid solution. It’s not sustainable. Having said that, rapid weight loss is medically necessary for a small number of people who are morbidly obese. However, they [should] also learn to manage the issues that contributed to their weight.”
Source
http://www.bodyandsoul.com.au/weight+loss/lose+weight/have+we+been+thinking+about+weight+loss+the+wrong+wayr,37223
