Weight gain myths
It could be your genes
Eating less (energy in) and exercising more (energy out) is the secret to a slimmer waistline. Or is it?
For years, health experts have considered this the ‘go-to’ formula for maintaining a healthy weight. But now its simplicity is being questioned. “The idea that all you need to do to lose weight and keep it off is to cut kilojoules and go to the gym regularly is not true for every person,” says Professor Joe Proietto, head of the Weight Control Clinic at Austin Health in Victoria.
“It’s one of numerous unhelpful myths that imply people are completely to blame for their weight gain. In fact, obesity is a disease affected by 100 genes that impact on weight. Up to 60 per cent of the population may be carrying some of these genes that predispose them to store fat and make it harder for them to lose it.”
UNHELPFUL WEIGHT MYTHS
That doesn’t mean that if you
have obesity genes you are destined to gain weight, but it does mean your risk of weight gain and obesity may be higher. So if you are often battling the scales, or have spent years yo-yo dieting, separating the following myths from facts may help you maintain a healthier weight:
MYTH 1: Slim people eat less than overweight or obese people.
We all know people who can eat whatever they want and not put on a kilo. Science is now telling us why. “There is growing evidence that there is a powerful genetic susceptibility to becoming obese,” says Proietto.
In one series of experiments at Rockefeller University in New York, a random group of lean people ate excess kilojoules for a period of time. Though they all over-ate by the same amount, they surprisingly showed a variety of weight gains – some participants put on a lot of weight while others didn’t.
“Since the volunteers were all fed the same number of kilojoules, the only way that this can be explained is that those who did not put on weight must have been better at burning it off,” observes Proietto. “This has been backed up by studies that show that identical twins have similar weights, even if they are reared in households where they eat differently.”
According to Proietto, studies also suggest that the level of voluntary activity we do, such as playing sport, may also be dictated by our genes. “Research at the Mayo clinic has also found that the amount that we burn off through fidgeting and other spontaneous movement appears to be genetically determined, too, and impacts on how much fat we store or burn,” he says.
PROTECT YOUR WEIGHT:
Lifestyle does play a role in weight gain and can cause epigenetic changes, which switch certain genes on and off.
“Those lifestyle triggers may include a high-fat, high-kilojoule diet and also stress and sleep loss,” explains Proietto. The take-home message? Aim to:
Eat a healthy diet with plenty of whole foods and limit take-away and processed foods.
Engage daily in a practice to reduce stress, such as meditation, progressive relaxation or yoga.
Stop bingeing on Netflix and make sure you get eight hours of sleep a night.
MYTH 2: Our bodies are designed to be slim.
Flashback to when we lived in caves and the genes that hardwired our bodies to store fat efficiently and quickly kept us alive in times of famine. “Fat was the preferred form of stored energy because it is light and, per gram, contains twice the energy stored in glucose,” says Proietto.
Cut to the present where food is readily available and those very same fat storage genes have become a liability. “Those genes are now widening our waistlines and causing health issues such as heart disease and diabetes type 2,” says Proietto.
Obesity genes not only cause some people to store more fat, they also affect their hunger hormones, increasing their appetite and leading to weight gain. “When the capacity of their fat cells to store fat is reached and fat begins to be deposited in other tissues, particularly muscle and liver (called ectopic fat), it can cause damage,” says Proietto. “In muscle, ectopic fat causes insulin resistance which, in susceptible individuals, is a precursor to type 2 diabetes. In the liver, excess fat not only causes insulin resistance but can also lead to fatty infiltration, causing cirrhosis.”
PROTECT YOUR WEIGHT:
Eat three meals a day, avoid snacking, cook from scratch where possible and don’t eat take-away more than once a week.
Fill your plate with mostly vegetables and a palmful of protein. If you are eating carbs, keep the serving small.
Minimise your intake of starchy vegetables like corn, peas and potato and eat more low-carb vegetables such as broccoli, spinach, tomatoes, zucchini, cauliflower, capsicum and salad greens.
Eat mindfully: “Research shows that when you focus fully on the enjoyment, texture and flavour of your food, you feel more satisfied after a meal and are less likely to snack later,” says Proietto.
Obesity is a disease affected by 100 genes that impact on weight
MYTH 3: Controlling hunger is about willpower.
“Many of the obese people that we see in our clinic tell us that they have stuck rigidly to diets in the past and lost weight – even large amounts – but have inevitably gained it back,” says Proietto. “This is not due to lack of willpower. Once some people lose weight their genes lead their brains to increase their hunger hormones so that they actually feel hungrier than before they lost the weight.”
Research from the University of Washington has found that fat loss due to kilojoule restriction causes a drop in the hormone leptin (which makes you feel full) while also increasing levels of the hormone ghrelin (which makes you feel hungrier).
“Our research has found these changes continue and that the hormones that increase hunger are still elevated 12 months and three years after weight loss,” says Proietto.
“This means that genes and not willpower make it difficult for some people to maintain their weight loss after a period of eating less.”
PROTECT YOUR WEIGHT:
Talk to your healthcare team about undertaking a ketogenic diet for several months to encourage weight loss. This is best done under the supervision of a nutritionist. In their
Weight Control Clinic at Austin Health, Proietto and his team prescribe a low-fat, low-carb ketogenic diet for people who have gained weight.
“I don’t use a high-fat, low-carb diet because having too many fats can have unhealthy impacts on the heart,” says Proietto. “People on our ketogenic diet eat 3347 kilojoules (800 calories) per day, replacing breakfast and lunch with protein drinks and eating a dinner of protein and non-starchy vegetables with a dash of oil to contract the gall bladder.”
For the first few days on the diet the body burns its glycogen stores. “I ask people to buy roast chicken and keep it in the fridge so they can nibble on it to stave off hunger,” says Proietto. “Usually by day three on the ketogenic diet, people start burning fat and start producing ketones – chemicals that suppress hunger.”
At Proietto’s clinic at Austin Health, people who are obese are advised to stay on the diet for as long as it takes them to reach a healthy weight, while a person who has less weight to lose may only stay on the ketogenic diet for a few months.
“The combination of the meal replacement and the lowcarbohydrate evening meal ensures that people obtain all the vitamins and minerals they need to stay healthy while losing weight,” he says.
Once some people lose weight their genes lead their brains to increase their hunger hormones
MYTH 4: Dieting is the best way to lose weight.
In fact it may cause rebound weight gain. A sobering study by the National Institutes of Health tracked six male and eight female contestants from the US television show
The Biggest Loser.
Though their body fat initially reduced with their weight loss, six years later when the contestants were followed up, their body fat had increased almost back to the same level it had been at the beginning of the program before their weight loss.
Meanwhile, their metabolisms were idling on slow. “The researchers found that six years later, the dieting had actually slowed the metabolism of the contestants by between 1255 and 2090 kilojoules a day (300 to 500 calories),” says Proietto.
PROTECT YOUR WEIGHT: Avoid constant dieting.
Not only is there a risk it could increase your hunger hormones, your energy expenditure – the rate at which you burn kilojoules – is also likely to drop at the same time. Instead, under the supervision of a nutritionist or your diabetes educator or endocrinologist, make some short-term changes or mix up your eating style.
This may include approaches like eating flexitarian (where you eat vegetarian several days a week) or intermittent fasting (where you eat lower kilojoules several days a week).
MYTH 5: If you lose weight quickly you are less likely to keep it off.
Proietto has undertaken a study of 200 obese people that showed this myth to be untrue. In his study for the National Health and Medical Research Council (NHMRC), volunteers were put into either the rapid weight loss group (who had to lose the weight over three months) or the slow weight loss group (who had to lose the same amount over nine months). “We checked their weight again three years after achieving the initial weight loss,” says Proietto. “This showed that there was no difference in the rate of weight regain between the two groups.”
PROTECT YOUR WEIGHT:
“If you are trying to engage in weight loss, remember that sometimes doing a shorter period of restricted kilojoules is far more effective than an extended period of kilojoule restriction, which might also have the unintended impact of slowing your metabolism,” says Proietto.