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Providing perspectives on recent research into vitamins and nutritionals


Chocolate: Good For the Heart But Not the Waistline?

By Julia Bird

Two years ago, we were excited to report that chocolate consumption was associated with lower body mass index, waist circumference and body fat in European teenagers. However, the results in adults turn this news pear-shaped: obesity and health researcher JA Greenberg and colleagues found that for every ounce per day chocolate that was habitually consumed, women in the US had an average increase in body weight of 0.9 kg over a three year period, and greater chocolate frequency was associated with greater increases in weight over six years. In addition, Nickols-Richardson and co-workers found no difference in body weight during a 18-week study of dark chocolate and non-chocolate snacks during a weight loss program. Koli and associates also sadly found that although reducing snack consumption over 8 weeks was effective in helping overweight adults lose a remarkably modest amount of weight (1 kg), consuming dark chocolate resulted in no change in weight. It appears that eating chocolate is not the weight loss solution that many of us dream of.

On the other hand, chocolate is a nutrient-dense food and contains biologically active chemicals. According to the USDA food database, a bar of milk chocolate contains more protein, fiber, calcium, iron, magnesium, phosphorus, potassium, zinc, riboflavin, and vitamins B12, A, E, K than a slice of wheat bread (food numbers 18064, 19120). The bioactive components are primarily a whole host of polyphenols, including flavanols. These are responsible for the antioxidant activity of, and the research interest in, chocolate.

As part of the FLAVIOLA project, Sansone and co-workers conducted a randomized controlled trial using cocoa flavanols in a concentrated powder. The 7g drink powder that was used as the intervention during the 1-month trial contained 450 mg cocoa flavanols. Using data from Miller, this is equivalent to the flavanol content of around a quarter of a cup of cocoa powder. Both the cocoa flavanol drink and the control also contained a drink base, coloring to ensure masking, and the control drink had added caffeine and theobromine to match the cocoa flavanol product. The authors do not report on whether the powder has an agreeable flavor. The 100 healthy, middle-aged men and women consumed either the cocoa-flavanol drink or the control twice a day for a month. Endpoints related to cardiovascular disease risk were assessed at baseline and weekly until the end of the study: flow mediated dilation, blood pressure, cholesterol  and Framingham Risk Score.

At the end of the intervention, people consuming the cocoa-flavanol product had improvements in flow-mediated dilation (a measure of vascular health), blood pressure, total cholesterol (decrease) and HDL-cholesterol (increase). These translated into a decrease in risk of heart attack, stroke and cardiovascular disease according to the Framingham Risk Calculator.

My thought with these studies is: what does this mean for me as a chocolate lover? Using once again the data from Miller, I would have to consume the following twice a day to meet the same flavanol intake as used in the study:

- 112.5 g dark chocolate assuming a flavanol content of 4 mg/g

- 28 g cooking chocolate assuming a flavanol content of 20 mg/g

- 900 g milk chocolate assuming a flavanol content of 0.5 mg/g

Unless I switch to eating cooking chocolate or cocoa powder (yuck!), I am not sure if I would be able to meet these levels of cocoa flavanol consumption without having unfavorable effects on my weight. However, the powder shows promise. I am just not sure if I will enjoy consuming it as much as chocolate, though.


Main citation:

Roberto Sansone, Ana Rodriguez-Mateos, Jan Heuel, David Falk, Dominik Schuler, Rabea Wagstaff, Gunter G. C. Kuhnle, Jeremy P. E. Spencer, Hagen Schroeter, Marc W. Merx, Malte Kelm and Christian Heiss. Cocoa flavanol intake improves endothelial function and Framingham Risk Score in healthy men and women: a randomised, controlled, double-masked trial: the Flaviola Health Study. British Journal of Nutrition, available on CJO2015. doi:10.1017/S0007114515002822.

Supporting citations:

Cuenca-García M, Ruiz JR, Ortega FB, Castillo MJ; HELENA study group. Association between chocolate consumption and fatness in European adolescents. Nutrition. 2014 Feb;30(2):236-9. doi: 10.1016/j.nut.2013.07.011. Epub 2013 Oct 17.

Greenberg JA, Manson JE, Buijsse B, Wang L, Allison MA, Neuhouser ML, Tinker L, Waring ME, Isasi CR, Martin LW, Thomson CA. Chocolate-candy consumption and 3-year weight gain among postmenopausal U.S. women. Obesity. 2015 Mar;23(3):677-83. doi: 10.1002/oby.20983. Epub 2015 Feb 3.

Greenberg JA, Buijsse B. Habitual chocolate consumption may increase body weight in a dose-response manner. PLoS One. 2013 Aug 7;8(8):e70271. doi: 10.1371/journal.pone.0070271. eCollection 2013.

Koli R, Köhler K, Tonteri E, Peltonen J, Tikkanen H, Fogelholm M. Dark chocolate and reduced snack consumption in mildly hypertensive adults: an intervention study. Nutr J. 2015 Aug 22;14(1):84. doi: 10.1186/s12937-015-0075-3.

Kenneth B. Miller, W. Jeffrey Hurst, Nancy Flannigan, Boxin Ou, C. Y. Lee, Nancy Smith, and David A. Stuart. Survey of Commercially Available Chocolate- and Cocoa-Containing Products in the United States. 2. Comparison of Flavan-3-ol Content with Nonfat Cocoa Solids, Total Polyphenols, and Percent Cacao. Journal of Agricultural and Food Chemistry 2009 57 (19), 9169-9180. DOI: 10.1021/jf901821x

Nickols-Richardson SM, Piehowski KE, Metzgar CJ, Miller DL, Preston AG. Changes in body weight, blood pressure and selected metabolic biomarkers with an energy-restricted diet including twice daily sweet snacks and once daily sugar-free beverage. Nutr Res Pract. 2014 Dec;8(6):695-704. doi: 10.4162/nrp.2014.8.6.695. Epub 2014 Nov 5.