Quite an interesting study was published recently: Body weight status and cardiovascular risk factors in adults by frequency of candy consumption fulltext.
The study investigated the correlation between frequent candy consumption and adiposity (waist circumference and triceps skinfold measurements) in 5817 adults and failed to find a link. Why was that?
The study was a retrospective epidemiological study (i.e., it looked at past survey data and crunched the numbers; it was not an intervention) using data from NHANES 2003-2006, a very large and semi-annual survey in the USA. It looked at the frequency of candy consumption (less than 3 occasions a month, more than 3.5 times a week, and in between), and although obesity seems to be the most interesting data point, other health parameters were also measured.
The investigators found that a higher intake of candy was associated with various potential confounds, including a higher overall caloric intake (around 200 calories more) and higher intake of both dietary fats and carbohydrates, along with a slightly lower protein intake (but no association with dietary fiber). When the researchers assessed the data and controlled for minimal confounds (sex, age, and race) and then controlled for more (education, social class, smoking, physical activity, and TV-watching time) in a second analysis, they failed to find an association between candy intake and adiposity. There was also a failure to find associations of any sort with insulin sensitivity, blood pressure, or lipoproteins.
Why is this interesting? This lack of association between candy consumption and obesity was still true when the observed dietary differences were not accounted for in the statistical analysis! Also, this is not a single, offhand observation; it has been observed (twice before). The oldest data suggest the opposite conclusion of higher candy intake being associated with slightly more obesity in older individuals, but noted more longevity with candy consumption as well.
The authors discussed that this may be due to the fact that candy contributes a very small overall amount of calories to the diet. Despite the poor "quality" of those calories, it was too small of a stressor to matter. They also mentioned offhand that the cocoa polyphenols found in chocolate (which was the predominant candy source) could have had beneficial effects.
They also noted that the higher reported intake of calories in frequent candy consumers may not be necessarily true, as self-reports are imperfect. Furthermore, while the three previous studies seem to be free from potential bias, this study was funded by the National Confectioners Association (NCA). The authors declared no competing interests, and the research design and conduct was independent of the NCA; the NCA appeared to give money and then pose the research question only.
A new retrospective epidemiological study found that chocolate candy did not correlate with obesity, even before the data was normalized for obvious potential confounding variables. This surprising result has been noted in the past as well.
Like all epidemiological studies, causation cannot be assigned and this study should be taken with a grain of salt. There is a potential conflict of interest due to the funding source, but the parameters given around the funding do not appear to significantly influence the outcome of the study.