Weight loss: What science says really works

Carole has been trying to lose weight for the past two years. She has tried weight watchers,  all number of different supplements but without any significant success. She has a very stressful family and work life leaving little time for exercise and has problems sleeping.

In 2014, 20.2% of Canadians aged 18 and older, roughly 5.3 million adults, were classified obese. (1) In 2013, it was estimated that Canadians spend nearly 7 billion dollars on weight loss products and programs. (2) There is much hype what works for weight loss but what does the current scientific research say.

What is best Diet for weight loss?

In a scientific paper recently published in the Lancet looking at the effectiveness of different diets for long-term weight loss, the researchers concluded that when compared with diets, the evidence does not support low-fat diets over other diets for long-term weight loss. (3) Other findings included:

• Low-carbohydrate diets led to significantly greater weight loss than did low-fat interventions.
• Low-fat diets did not result in differences in weight change compared with other higher-fat diets.
• Higher-fat weight loss diets led to significantly greater weight loss than low-fat interventions.

These findings go some way to dispelling the idea that low-fat diets are an effective intervention for long-term weight loss. On the contrary, it appears that a high fat, low carb is a better approach based on current evidence. This conclusion is backed up by findings from a study looking at the effect of a Mediterranean, high-fat, low carbohydrate diet, which found it had a significant impact on weight loss. (4)

What about exercise?

There is a commonly held belief that you need to do exercise to lose weight but is this true. When looking at the scientific data increasing exercise without any other changes has a modest effect on weight. (5) However, moderate exercise combined with other lifestyle interventions clearly had a significant influence on weight. (6)

Does sleep affect weight?

There is robust scientific research to show that poor sleep has a negative effect on overall health as well as weight. (7) A review paper found that reduced sleep duration is a causal factor of weight gain. (8)

What about stress?

While stress has a negative impact on health, there is only weak evidence that it causes weight gain. (9)

In conclusion

Lifestyle factors such as poor diet, sleep and lack of exercise can cause weight gain. When considering a weight loss program, the evidence points to one that includes a Mediterranean high-fat, low carb style diet, moderate exercise, and adequate sleep. While there is only weak evidence that stress alone causes weight gain it would be foolish to ignore because of the negative effects stress has on health. (10)

Disclaimer

This article in not intended to provide medical advice, diagnosis or treatment.