Carrying a misleading headline, and some not-quite-accurate and confusing descriptions of the study, this news release describes research designed to evaluate the impact on overweight or obese teens of complying with a healthier snacking regimen — one involving peanuts and peanut butter. It could have been markedly strengthened by less emphasis on quotes stating the obvious and questionable (“…unhealthy eating habit(s) can lead to an unhealthy weight”; “snacking is more common during the adolescent years”), and more emphasis on the design, context and hopeful outcome of this small, but rigorous randomized controlled intervention trial.
Families, students, schools, and public health specialists are in a frustrating battle to prevent and address obesity and its damaging consequences. As this release notes, this may be especially true in poor, urban and minority children and teens whose diets are more likely to be composed of fast food meals, and sugary, greasy, nutritionally deficient snacks after school. Widely publicized efforts — like New York City’s ban on large-sized soda pop sales — to introduce teens (and adults) to healthier diets, haven’t seemed to do much to increase desire for carrot sticks, fruit, and yogurt in these populations. So any study that suggests a) it really is possible to get teens to try, and to stick with a nutrient-rich snack like peanuts instead of unhealthy snacks; b) that providing such snacks may reduce body mass index despite the peanut’s high energy content; and c) a snack may find favor with adolescents’ famously picky food preferences, is bound to get attention, even if the good results are modest and the trial relatively small.
The release didn’t address costs, but we won’t penalize it because peanuts cost, well, peanuts.
That being said, the release could have been improved by the addition of some context about the high costs of eating well, especially in urban food deserts and among families without the time, transport, and resources to buy, cook, and eat fresh food.
The release confuses or misses some key points about the study and the data it obtained and set out to measure. The intervention was not a “12-week” study, but lasted six months overall. Moreover, the goal of the study was not to measure the impact of eating peanuts on weight loss. It was to compare the weight loss or BMI-reduction outcomes in Mexican-American children who were either high adherents or low adherents to a suggested (and freely offered) snack of peanuts or peanut butter on a daily basis at the end of the school day. And the study also included educational and physical activity components. The release is unclear about the actual number of students in the comparison groups who lost weight. It is silent on how much the teens weighed on average or across a range at the start and end of the study in the comparison groups, and it tells us nothing about the number of calories in the snacks or how much physical activity was involved. The published abstract did not either, but presumably the full study was available in the preparation of the release. The release does note that students who got the snack more regularly decreased their overall BMI by .7kg/m2 compared to those who did not get the snack regularly, but most readers will not do the math or understand what the figure means. It needs to be pointed out that the 0.7kg/m2 drop was not deemed statistically significant, even by way of the often-denigrated p value where it was found to be 0.21 (a value less than .05 is traditionally deemed “significant”). It’s also worth noting that the absolute difference in weight between the two groups was the high adherence kids GAINING 1.54 pounds less than the low adherence kids — a difference deemed not to be statistically significant either (P 0.63).
The release notes that care was taken not to give these snacks to children who had nut allergies.
The release really needed more information about the nature and quality of the intervention. For instance, it did not note that adherence was measured by responses to a peanut food frequency questionnaire (a measure that can be weak depending on who is filling it out and under what circumstances) or that skin fold tests did not significantly decrease. And it offers a quote suggesting the kids might not be eating a good meal at school. There’s no data offered that tells the reader how many study participants ate school-provided lunches or other meals during the school day, and no real effort to explore or explain how other variables might have affected things. It’s important to note that this was a secondary analysis and it’s impossible to conclude that it was the peanut snacks and not some other aspect of the intervention (which included nutrition education and physical activity). The study states that the authors, “did not collect other nutrition education or physical education data to control for adherence to the intervention program in the analysis.”
No mongering, but the quotes from the lead researcher used in the release made a lot of assumptions about the study population’s lack of supervision, “structure” at home, inactivity and eating habits without providing supporting evidence.
The release notes that the participants are part of an ongoing study of obesity interventions, but never says the study was federally funded, or how the snacks were paid for (or donated).
The release quotes a researcher who says “there hasn’t been a lot shown to be very effective on a large scale” for childhood obesity. That’s true enough, but we thought the release needed to go a little bit further to earn a Satisfactory rating. This is a very active area of study, and the release could have given a few examples of what — besides peanuts — has been tried and what the results have been.
It’s common knowledge that peanuts and peanut butter are available in every grocery and convenience store in the United States.
The release doesn’t make clear what’s novel about the research. Prior to this research it was already widely accepted that choosing healthy snacks (along with physical activity) over unhealthy ones is helpful in preventing weight gain.
The news release doesn’t cross the line it its claims. However, the selected quotes used in the release make broad statements that appear to make more judgments about the study population than about the data gathered in the study.