A new study finds that consuming chocolate may positively affect blood sugar and other health markers. So, what’s the key to chocolate’s health benefits? Researchers chalk them up to a favorable nutrient profile and, surprisingly, the time of day the chocolate is consumed.
What did the study investigate?
This novel study aimed to quantify the impact of chocolate consumption and its timing on weight, waist circumference, satiety, fasting blood glucose, and gut microbiome composition. Researchers at the University of Murcia in Spain enrolled 19 postmenopausal women with BMIs under 35 kg/m2 into a randomized controlled trial. Each participant was randomly assigned to consume 100g of milk chocolate in the morning, at night, or abstain from chocolate altogether (control group) for two weeks while eating all other meals as they typically would. Here’s what the researchers uncovered.
Chocolate consumption showed some surprisingly impressive outcomes
Despite the additional 542 kcal/day chocolate treat, women in the chocolate groups reduced daily energy intake by ~300 calories when eating chocolate in the morning and by ~150 kcal/day when eating chocolate in the evening. Interestingly, women who ate chocolate in the morning significantly reduced their waist circumference by 1.7% compared to the control. In addition, the women in both the morning and evening chocolate groups reported decreased hunger and desire for sweets compared to the women who abstained from eating chocolate. The study found no significant difference in body weight between any of the groups.
Figure 1: Weight status baseline vs. end of experiment. No significant changes in body weight (baseline vs. follow-up) occurred (p>0.05). 
Chocolate even impacted participants on a biomarker level. Milk chocolate is known for being relatively high in sugar, especially compared to dark chocolate. Despite the sugar content, this study found that eating milk chocolate in the morning actually reduced fasting blood glucose by 4.4% compared to control.
And this tasty treat also contributed to favorable changes in the gut microbiome. Both a morning and evening chocolate treat were associated with increased diversity of microbes, indicative of good gut health. What’s more, chocolate led to a higher abundance of Actinobacteria (typically good gut bacteria) and a lower abundance of Firmicutes (typically bad bacteria) in the gut. Nighttime chocolate consumption was also associated with a higher concentration of short-chain fatty acids (SCFA), which positively impacts the gut microbiome.
What can these benefits be attributed to?
The researchers have a theory to explain why a morning dose of chocolate may elicit favorable changes in fasting blood glucose: “Chocolate may improve glucose homeostasis by slowing carbohydrate digestion and absorption. Indeed, cocoa could reduce the rate and extent of macronutrient digestion by binding to and antagonizing digestive enzymes.”  Slowing down the rate of digestion is especially important in preventing large blood glucose spikes after a meal.
Researchers hypothesize that the weight-neutral impact of chocolate may be a response to the cocoa’s polyphenol-rich composition, which includes epicatechins and catechins. Dietary polyphenols, like those found in cocoa, are also well known for their positive impacts on the abundance of good gut bacteria, an indicator of optimal gut health. What’s more, the small but present amount of fiber in chocolate, 1.8g to be exact, may contribute to the increased concentration of SCFA, which supports the gut’s good bacteria.
Is eating chocolate at breakfast actually healthy?
Chocolate can be a part of an overall healthy diet. So yes, eating chocolate at breakfast can be healthy and may potentially come with a few perks (like eating fewer calories throughout the day and better blood glucose control).
But, the researchers were sure to note the caveats of this study. With a sample size of just 19 and a limited participant pool (all were postmenopausal females), study findings may not be generalizable to other populations. Additionally, the study could not conclusively determine the specific reasons that chocolate had beneficial health effects, e.g. chocolate’s epicatechins, caloric density, etc.
Although this new study shows promising results, further research on the impact of chocolate is warranted in a more diverse group of people. Are you interested in adding chocolate to your daily routine? Here are our science-backed tips.
This study was published in the FASEB Journal, July 2021.
Michelle Darian, MS, MPH, RDMichelle is a Nutrition Specialist at InsideTracker. As a Registered Dietitian, you’ll find Michelle analyzing the research behind recent nutrition trends, bringing actionable food and supplement recommendations to the platform. When she's not myth-busting, Michelle can be found exploring new restaurants and getting creative in her kitchen.
 Teresa Hernández‐González, Rocío González‐Barrio, Carolina Escobar, Juan Antonio Madrid, Maria Jesús Periago, Maria Carmen Collado, Frank A. J. L. Scheer, Marta Garaulet. Timing of chocolate intake affects hunger, substrate oxidation, and microbiota: A randomized controlled trial. The FASEB Journal, 2021; 35 (7) DOI: 10.1096/fj.202002770RR. https://pubmed.ncbi.nlm.nih.gov/34164846/