Carbohydrate Intake Not Significantly Correlated With Weight Gain

Carbohydrate, fiber, and sucrose intake show no significant association in relation to weight gain in adults, according to results published in International Journal of Obesity.

As a worldwide public health issue, the obesity epidemic is still lacking effective ways to decrease its burden. A diet high in carbohydrates has been suggested to promote weight gain, and the roles of quantity and quality of various carbohydrates remains to be investigated. Researchers aimed to evaluate weight change in relation to carbohydrate intake, dietary fiber, total sugars, and sucrose.

A population-based cohort study was conducted on 3 follow-up studies on health and lifestyles from 2004 to 2014: the Health 2000 and 2011 Health Examination Surveys (Health 2000); the clinical examinations of the Helsinki Birth Cohort Study (HBCS) 2001−2004 and 2011−2013; and the Dietary, Lifestyle, and Genetic Determinants of Obesity and the Metabolic Syndrome (DILGOM) Study 2007 and 2014. All studies consisted of food frequency questionnaire (FFQ) at baseline and follow up. Food frequency and portion sizes were reported over a 12-month period for each study. Quantitative food consumption (grams/day [g/d]), nutrient (g/d), and energy intake (kilojoules [k]/d) were all recorded. Participants who completed the FFQ with information on body weight and BMI at baseline and follow up were included in the study. Participants aged over 70 years, who had a BMI lower than 18.5 kg/m², or who were pregnant were excluded from the study.

A total of 8327 participants were included in the final cohort. The researchers followed the participants for 7.2, 10.3, and 11.0 years in each of the studies: DILGOM, HBCS and Health 2000, respectively. At baseline, mean BMI was 27kg/m2 and the proportion of participants with obesity was around 20% in all studies. Weight gain during follow up was noted in the Health 2000 and DILGOM studies (1.8 and 1.0 Kg, respectively), whereas HBCS had an mean weight loss of -1.4Kg. The mean change in waist circumference increased in all cohorts (Health 2000: 2.7 cm; HBCS: 1.4 cm; DILGOM: 2.3 cm).

During total follow up, mean carbohydrate intake from each study decreased in all participants (42% in Health 2000, 48% in HBCS, and 65% in DILGOM). However, when follow-up time was standardized to 7 years across all 3 studies, no significant associations were observed in total carbohydrate, dietary fiber, total sugar, or sucrose intake and risk for weight gain of at least 5%.

The researchers noted an association between total sugar intake and weight gain. Amongst overweight participants, total sugar intake was associated with a higher risk for weight gain (risk ratio [RR], 1.36; 95% CI, 1.01-1.84). Notably, amongst those who were obese, a near inverse relationship was found with sugar intake and risk of weight gain (RR, 0.63; 95% CI, 0.40-1.00).

In participants with a deceased mean carbohydrate intake, sucrose intake was found to have a protective association in participants with weight gain (RR, 0.78; 95% CI, 0.61-1.00), however this association was not found in other groups.

Study limitations include self reporting dietary data, which could potentially lead to misreporting, and the 5% cut off for major weight gain.

The researchers concluded that despite the lack of association between weight gain and carbohydrate intake, “the findings have been, in general, highly inconsistent, [and] further research is warranted from different populations and with modern data to elucidate the relation of carbohydrate quantity and quality with weight gain.”