Yes, moms’ healthy habits can reduce childhood obesity. No, that won’t solve our obesity crisis

When mothers follow five healthy lifestyle habits — eating a high-quality diet, exercising regularly, maintaining a healthy weight, drinking alcohol in moderation and not smoking — their children are 75 percent less likely to become obese than the children of moms who don’t follow any of those habits, according to a study published online this week in the journal BMJ (formerly known as the British Medical Journal).

This finding underscores the “potentially critical role” that mothers’ lifestyle choices have on whether or not their children become obese, say the study’s Harvard University authors.

It also lends “support to family or parent based intervention strategies for reducing childhood obesity risk,” the researchers add.

When I read that conclusion at the end of the paper, I sighed. Here’s yet another study that appears to assign, wittingly or not, the burden of ending the childhood obesity epidemic to individuals — specifically, to moms.

What about the role of dads in the epidemic? 

But more important, what about the role of society? Why do we continue to put the responsibility for turning around the obesity epidemic on individuals when it’s long-past clear that a much more comprehensive approach is needed?

I’ll get back to that issue in a minute. First, a look at the new study.

Looking for links

The data for the Harvard study was collected from 24,289 children between the ages of 9 and 14 born to 16,945 women who are part of the ongoing Nurses’ Health Study II. The children were part of a separate study known as the Growing Up Today Study.

The data revealed that over a five-year period, 1,282 of the children — or 5.3 percent — had become obese. The researchers then looked to see if there was an association between the children’s obesity and the mothers’ adherence (or lack of it) to the five healthy lifestyle habits. 

Here’s what they found:

• The children whose mothers had a healthy body mass index (18.5 to 24.9) were 56 percent less likely to be obese than those whose mothers were overweight.
• The children of mothers who did not smoke were 31 percent less likely to be obese than those of mothers who were smokers.
• The children of mothers who engaged in at least 150 minutes per week of moderate to vigorous physical activity were 21 percent less likely to be obese than those whose mothers were less active. 
• The children of mothers who consumed alcohol in moderation (1 to 14.9 grams per day) were 12 percent less likely to be obese than those whose mothers abstained from alcohol. (Too few women in the Nurses’ Health Study were heavy drinkers to determine an association between the heavy use of alcohol and the risk of obesity in children.)

Interestingly, no link was found between the children’s obesity and their mothers’ eating habits. This unexpected finding may be because children’s diets are influenced by factors outside the home, such as the meals the children are served at school or their friends’ eating habits, the Harvard researchers point out. Or it may be because children who are overweight tend to underreport how much food they eat. (This study relied on moms and kids self-reporting their dietary habits.)

Still, when a high-quality diet was added to the other healthy habits, the children of moms who engaged in all five habits were 75 percent less likely to be obese.

And when both moms and their kids stuck to those healthy habits, the risk dropped even more, by 82 percent.

“Our study was the first to demonstrate that an overall healthy lifestyle really outweighs any individual healthy lifestyle factors followed by mothers when it comes to lowering the risk of obesity in their children,” said Qi Sun, the study’s senior author and a professor of nutrition at Harvard University, in a released statement.

Demographics 

The study comes with several important caveats — ones that should be considered not only when thinking about the study’s results, but also when pondering its implications for solving the obesity epidemic. 

In addition to being an observational study (and thus not able to prove cause-and-effect), the women who participated in the study came from relatively homogenous socioeconomic and educational backgrounds — ones that tended to be wealthier and more educated than those of most other American women. Almost a third (32.5 percent) of the mothers in the study had annual household incomes of $100,000-plus, and slightly fewer (30.1 percent) had graduate degrees. 

That might explain why the rate of obesity among the participants’ children — 5.3 percent — was so much lower than the U.S. national average of 18.5 percent. 

Socioeconomic status makes a difference in the risk of obesity — for both adults and children. Study after study has shown that people from lower socioeconomic backgrounds face much greater barriers to following a healthy lifestyle than those who are better off financially. Here are just a few of those research findings, as described by the nonprofit Food Research & Action Center:

• Low-income neighborhoods frequently lack full-service grocery stores and farmers’ markets where residents can buy a variety of high-quality fruits, vegetables, whole grains, and low-fat dairy products.  Instead, residents  — especially those without reliable transportation — may be limited to shopping at small neighborhood convenience and corner stores, where fresh produce and low-fat items are limited, if available at all. 

• When available, healthy food may be more expensive in terms of the monetary cost as well as (for perishable items) the potential for waste, whereas refined grains, added sugars, and fats are generally inexpensive, palatable, and readily available in low-income communities.

• When available, healthy food — especially fresh produce — is often of poorer quality in lower income neighborhoods, which diminishes the appeal of these items to buyers.

• Those who are eating less or skipping meals to stretch food budgets may overeat when food does become available, resulting in chronic ups and downs in food intake that can contribute to weight gain. 

• Members of low-income families, including children, may face high levels of stress and poor mental health (e.g., anxiety, depression) due to the financial and emotional pressures of food insecurity, low-wage work, lack of access to health care, inadequate transportation, poor housing, neighborhood violence, and other factors. … Stress and poor mental health may lead to weight gain through stress-induced hormonal and metabolic changes as well as unhealthful eating behaviors and physical inactivity.

• Lower income neighborhoods have fewer physical activity resources than higher income neighborhoods, including fewer parks, green spaces, and recreational facilities, making it difficult to lead a physically active lifestyle. Research shows that limited access to such resources is a risk factor for obesity.

• When available, physical activity resources may not be attractive places to play or be physically active because low-income neighborhoods often have fewer natural features (e.g., trees), more visible signs of trash and disrepair, and more noise.

• Crime, traffic, and unsafe playground equipment are common barriers to physical activity in low-income communities. Because of these and other safety concerns, children and adults alike are more likely to stay indoors and engage in sedentary activities, such as watching television or playing video games. 

• Students in low-income schools spend less time being active during physical education classes and are less likely to have recess, both of which are of particular concern given the already limited opportunities for physical activity in their communities. 

• Low-income children are less likely to participate in organized sports. This is consistent with reports by low-income parents that expense and transportation problems are barriers to their children’s participation in physical activities.

The lifestyle choices of mothers — and fathers — do play a crucial role in the health of their children, as the Harvard study suggests. But if we want to help parents improve those lifestyle choices — and lower the U.S. childhood obesity rate — targeting parents with individually based intervention strategies won’t have much effect. 

We need a much broader approach — one that tackles poverty and thus gives everyone equal access to a healthy lifestyle.

FMI: You can read the Harvard study on the BMJ website.