Over the years, we have been flooded with information and heard the same advice many times over: “Just make minor changes to your diet, and maybe add a little exercise, and over time, you will lose weight”. As many people have experienced, this is often not the case.
Hamish van Wyk, Registered Dietitian and Diabetes educator from the Centre for Diabetes and Endocrinology (CDE), says that it is important to understand some of the common weight loss myths. “Without accurate information, people are bound for weight-loss failure, which is highly demotivating, particularly if you feel you are doing everything right and just not getting the results.”
Van Wyk believes that with so much clutter in the market place, it is definitely worth debunking some of the myths around weight loss and seeing what evidence-based nutrition is telling us.
Myth 1 – Small significant changes in food intake or exercise will produce significant weight loss
A 2013 study by some of the leading minds in nutrition showed that this belief is false.
Significant weight loss requires at least a moderate daily calorie restriction of 500 to 1 000 calories (or 2 100 – 4 200 kJ) relative to your usual energy intake. To put that into perspective, to achieve a daily 500-calorie reduction by cutting out bread alone, you would need to eat seven less slices of bread per day. If you were just cutting out sugar, you would need to reduce your intake by 31 teaspoons per day.
“You can now appreciate that when people just think that they can cut out one or two slices of bread per day or have less sugar in their coffee, this approach will never be effective.”
Unfortunately, minor increases in exercise also do not appear to work. Without addressing your dietary intake, you will need to do roughly two hours of exercise per day to lose weight. You really can’t ‘out exercise’ a bad diet.
Myth 2 – If you lose weight too quickly, you will put it back on just as quickly
Van Wyk shows the latest evidence is contrary to this thinking – the best results appear to come from a very low-calorie diet of roughly 800 kilocalories a day. These diets produce roughly a 2,5 kg weight loss per week as opposed to a moderate diet where you lose 0.5 to 1 kg per week.
“The evidence shows that there is no proof that if you lose more weight rapidly you will put it back on more quickly when you return to a more normal meal pattern. Fast, rapid weight loss may increase motivation and be a more effective means of shedding kilos and keeping them off.”
It is incredible to see that despite the very low-calorie intake, patients are often highly-motivated when they see the weight coming off for the first time, added Van Wyk. Very low-calorie diets are typically achieved through total meal replacement therapy, which is followed for eight to 12 weeks. Thereafter, food is gradually reintroduced.
“We do not advocate people trying these highly reduced calorie diets unless they are under the supervision of a registered dietitian who can monitor weight loss, and educate and coach the person to achieve a healthier relationship with food. In some high-risk individuals, a doctor is essential to reduce medication dosages as weight is lost, and to mitigate any possible medical risks consequent to the weight loss,” concludes van Wyk.