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Weight loss myths and misconceptions: Separating fact from fiction

Differentiating between the facts and the fiction on obesity and weight loss has important implications for how we should think and ultimately act when it comes to obesity prevention, management and treatment.

This past week, a major study published in the New England Journal of Medicine and authored by a panel of experts, attempted to uncover the truth about some popular myths, presumptions and facts related to obesity and weight loss. Using both popular media and scientific literature, the idea was to identify, challenge and expose some of our most common and widely held beliefs.

The article began by identifying seven myths, which are commonly held beliefs that persist despite contradictory evidence. I’ll list the article’s findings then offer my own opinions and insights as to what they might mean for you.

1. Small changes (skipping the Starbucks cookie) lead to large and lasting weight loss.

The body responds to minor fluctuations in energy balance by either revving up the system or slowing it down. ‘”Small” in this case likely refers to changes less than ~500kcal per day (of either decreased intake or increased expenditure).

2. Setting realistic weight loss goals is essential.


I’d tend to disagree that setting (realistic) goals is not important. Perhaps the problem is how and what we decide is realistic for us.

3. Slow gradual weight loss is safer than large, rapid changes.

For some people, large and relatively quick weight loss is potentially life-saving. As mentioned, slow gradual changes might actually be harder to accomplish.

4. Stage of change or diet ‘readiness’ is important for those wanting to lose weight.

Sometimes we must change even that which we do not want to change.

5. Phys Ed classes help reduce and prevent childhood obesity.

A 75-min class is only a small part of a much longer day. That isn’t to say they don’t or shouldn’t matter.

6. Breast-feeding  protects against obesity.

Perhaps not, but it does provides a number of other important health benefits.

7. Sex burns 100 to 300 kcal.

The article suggests the actual amount is more like 21. Maybe we’re doing it wrong?

Next, the article spells out six presumptions about obesity, which again are widely accepted and commonly held beliefs, but are neither supported nor refuted by scientific evidence. They require more investigation:

1. Eating breakfast protects against obesity.

I would say it doesn’t hurt and would argue it can reduce the amount of overeating later in the day. For runners, getting some energy early in the day will help you get through your run whenever it may occur.

2. Exercise and eating habits are learned in early childhood and influence our weight as adults.

Regardless of what we did as kids, as adults we are free to make informed decisions about what we eat and whether we are active.

3. Eating  fruits and vegetables helps to lose weight.

Maybe not, but it certainly should be part of your daily healthy diet and provides essential vitamins and minerals.

4. Yo-yo dieting is dangerous.

If not dangerous, certainly not effective at achieving the goal of lasting weight loss.

5. Snacking leads to weight gain.

Excessive energy intake leads to weight gain. Snacking can be an important means of getting energy when and where we need it.

6. Our built environment, e.g. sidewalks and park availability, directly contributes to obesity.

Buildings and parks don’t determine what we eat or whether we are active, although they can certainly cause a headache and make things more difficult.

Finally, the article mentions nine ‘facts’ for which there is a substantial amount of evidence to support and which have important implications for both the prevention and treatment of obesity:

1. Genetics play an important role, but does not determine destiny. Our choices and behaviours also play an important part.

I’ll never win Boston or go to the Olympics; I’ve accepted that. But that doesn’t mean I can’t work to be the healthiest, fittest and fastest individual I can possibly be.

2. Dieting is effective in the short-term, but generally do not work well in the long-term.

Want to lose five pounds? Don’t eat for five days. Yes, dieting does work for awhile. But long-term weight control requires a long-term plan and strategy.

3. Increased physical activity (exercise) improves our health.

Duh, of course it does! In addition to physical/fitness, it also provides a plethora of amazing psychological and social benefits as well.

4. Being sufficiently physically activity can help control and maintain weight.

Not sure what ‘sufficiently’ means exactly but in general, being consistently physically active can and does lead to weight control and stabilization.

5. Controlling and maintaining weight is something that must be worked at continuously.

As runners we can relate. Being successful at anything requires perseverance, consistency and long-term commitment.

6. For overweight children, programs that involve the parents and the home setting promote greater weight loss.

Being in a familiar setting and having a supportive network can and do have powerful effects on what we can accomplish.

7. A greater structuring of meals and use of meal-replacement products promote greater weight loss when compared to those that promote balance, variety and moderation.

As with running and training, having a structure and the timing right are keys to success.

8. Some weight loss drugs help patients lose and maintain their weight.

Some drugs work for some people, but what works for one will not work for all.

9. In some patients, bariatric surgery results in long-term weight loss.

Again, for some people, this may be the only effective option; but it won’t work for everyone.

The article concludes by saying that false and scientifically unsupported beliefs about obesity and weight loss are extremely common in both the scientific literature as well as the popular press. Differentiating between fact and fiction has important implications for how we should think and ultimately act when it comes to obesity prevention, management and treatment. This is also true for the many health and fitness claims being made or the many workouts, training programs and running products aimed for your consumption.

What are your thoughts? Any other common myths and misconceptions you feel were missed? How might they relate to your running?