A new study from the New England Journal of Medicine is making a lot of headlines and leading to questions about what we know and don’t know about weight loss and obesity.
The authors discuss common myths and beliefs related to successful weight loss strategies they say are not supported by evidence.
This is an important topic for us because AICR’s first recommendation for cancer prevention is “to be as lean as possible within the normal range of body weight.” This is because overweight and obesity is a cause of seven cancers, including breast (postmenopausal), colorectal and endometrial.
While this article is provocative, several of the authors’ myths and presumptions, as written, are not actually what health professionals are saying. For example:
Myth 1: Small sustained changes in energy intake or expenditure will produce large, long-term weight changes.
The key words used here are “large, long-term” weight changes. The idea behind small and sustained changes in diet and physical activity is that this is a way to get started – and to begin to build up to larger changes which in turn will help with long-term meaningful weight loss. James O. Hill, Ph.D. is one researcher who promotes this idea based on his published research. This study showed that a small change (reducing 100 calories per day) does result in a lower intake in the short term. Others have shown small changes leading to weight loss that was maintained 9 months later.
Presumption 3: Eating more fruits and vegetables will result in weight loss or less weight gain, regardless of whether any other changes to one’s behavior or environment are made.
The message from AICR, the 2010 Dietary Guidelines for Americans and other health organizations is to replace higher calorie foods, like fried foods or high fat meats, with vegetables and fruits. These lower calorie foods help with weight control and they help reduce risk of several cancers such as oral, esophageal and stomach.
There are strong long-term studies to support making small changes and including vegetables and fruits in your diet to promote weight loss and prevent weight gain. Last year, I wrote about one year-long study looking at what behavior changes added up to weight loss – one of the strategies that worked was eating more vegetables and fruit.
Weight loss is a long term process, and certainly no one thing is a magic bullet, but starting with one small step puts you on a healthier path. So don’t let one study dissuade you from taking the kind of steps that will help you achieve and maintain a healthy weight.
While the story is provocative, I wonder how much of it is funded by Big Food. There’s two recent articles I’ve read which talk about what Big Food is doing to legitimize their brands and how they’re getting in bed with researchers. Here’s one on coke and nutritionism: http://www.huffingtonpost.com/kristin-wartman/new-report-big-food-coopt_b_2550294.html.
Here’s one on the article that you mention above:
We are in danger when research gets done with support of or ties to well funded food companies.
Thank you for your comment. The article was partially funded by the National Institutes of Health, but you can see the disclosures from all the authors here: http://www.nejm.org/doi/full/10.1056/NEJMsa1208051.
I know for me that small changes in my diet and exercise routine have made a huge improvement in my health. In one year’s time from 01/2012 – 01/2013 I’ve lost 83 lbs. I started with simply walking once a day for about 25 mins, then added in two more short walks(1 – 15 min & 1 – 25 min) and then in 12/2012 I added step aerobics 2 -3 times a week. In addition to my weight loss, my blood sugar, cholesterol and triglycerides are all at normal levels with no medication. I have adopted a vegan diet in the last few months and have seen even more dramatic improvement in blood sugar control.
I want to point out that in your article you mentioned ‘obesity is a cause of seven cancers, including breast (postmenopausal), colorectal and endometrial.’ This is not a true statement. Obesity definitely increases the risk of all the above mentioned cancers (and more) but there is no evicence yet that it can cause any of them. There is a huge differnce between ‘increasing the risk’ and ‘causing’ a disease. Unless controlled clinical trials are done, the word ’cause’ should be used with caution.
I guess the above mentioned NEJM article was trying to get that same point out about evidence-based medicine versus anecdotal medicine.
Please check the link from NCI:
Thank you for your comment. The evidence is actually strong enough that researchers are using the word “cause” for excess body fatness and certain cancers. Dr. Walter Willett discusses the strength of the evidence in this NCI Bulletin article (http://www.cancer.gov/ncicancerbulletin/080712/page4). American Cancer Society also discusses overweight/obesity as a cause of postmenopausal breast cancer here: http://www.cancer.org/cancer/news/expertvoices/post/2012/10/11/does-being-overweight-cause-breast-cancer.aspx. While it is not the only cause of these cancers, many cases could be prevented if more people would be at their healthy weight.
I have utmost respect for Dr. Willet’s work but being an experimental scientist I will be still very wary to use the word ’cause’. We know from our past that studies with strong evidence in cohort studies have failed in clinical trials.
Thanks for pointing out the ACS article on breast cancer. I think unless more work is done to elucidate the underlying mechanism of how obesity causes breast cancer, I will still consider it a very strong risk factor for postmenopausal women. As a cancer researcher myself who is passionate about prevention, I would love to see the day when we have undisputable evidence like we have for smoking and lung cancer.
Said that, I 100% agree with you that losing excess weight should be the top priority for most individuals who wish to lead a healthy life and prevent different forms of cancer.
I do not wish to offend anyone, just wish to express my views. Thanks.
Yes, there is no controversy that a healthy weight is one of the most important goals for a healthier life for many Americans. We have far too many cases of type 2 diabetes, heart disease and cancer related to poor habits of diet, weight and physical activity. Thank you for your comments and your commitment to prevention and healthy lifestyles. Best, Alice
I love this article! A debt of gratitude is in order for sharing
a lot of information.