The idea that eating chocolate every day could aid in weight loss sounds appealing. However, the relationship between chocolate and weight management is complex and often misrepresented. While some studies suggest potential benefits, it's crucial to approach these claims with skepticism and consider the broader context. This article delves into the science behind chocolate and its effects on weight, examining the evidence, debunking myths, and offering a balanced perspective.
The Chocolate Diet Hoax: Exposing Junk Science
In a revealing exposé, a team of researchers and filmmakers demonstrated how easily bad science can be turned into sensational headlines. They conducted a bogus diet study, which was a carefully planned effort to expose the prevalence of junk science and unchecked, hype-driven press coverage. This sting operation highlighted the importance of critical thinking when evaluating diet and nutrition news.
The team, led by science journalist John Bohannon and German TV producer Peter Onneken, designed a clinical trial where participants were divided into three groups: a low-carb diet group, a low-carb diet plus 1.5 ounces of dark chocolate per day group, and a control group with their regular diets. After 21 days, the chocolate-eating group showed a slightly faster weight loss (about 10 percent) than the other dieters.
However, the study was intentionally flawed. With a small sample size and measuring 18 different parameters, the researchers knew they were likely to find at least one statistically significant result by chance. The study was published in the International Archives of Medicine, a journal known for publishing studies for a fee without rigorous peer review.
The researchers then wrote press releases that caught the attention of major news outlets. The media frenzy that followed exposed how easily the public can be misled by poorly conducted research and sensationalized reporting. As Bohannon noted, the world is drowning in pseudoscience about diet and nutrition, and even when there is science, it's very poorly reported.
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Dark Chocolate: Potential Benefits and Considerations
Despite the chocolate diet hoax, dark chocolate has some potential health benefits. Dark chocolate is derived from the cocoa bean and often has a higher cocoa content compared to its milk chocolate counterpart. Research has hypothesized that polyphenol rich dark chocolate has a beneficial effect on fat and carbohydrate metabolism, as well as on satiety, or that simply a small, sweet snack reduces food cravings and thereby can aid in weight loss. Dark chocolate contains powerful antioxidants, including flavonols like epicatechin, which can improve brain function, boost athletic performance, and reduce stress. Flavonols in dark chocolate have a positive impact on brain function, including better reaction time, visual-spatial awareness and stronger memory. The epicatechin in dark chocolate increases the production of nitric oxide in the blood, which supports circulation and reduces the amount of oxygen an athlete uses while engaged in moderately intense exercise. People who ate dark chocolate reported that they felt less stressed, and researchers confirmed that after eating dark chocolate, there were reduced levels of the stress hormone cortisol. The higher the cocoa content, the more beneficial flavonols the chocolate contains.
However, it's essential to consider the broader context. Dark chocolate is energy-dense (531 kcal per 100 g, on average) and can contribute, like any other food, to weight gain if eaten in excess. Weight gain (or weight loss) results from an imbalance between calories consumed and calories used by our bodies. It also contains saturated fats and added sugars, which should be limited in a healthy diet.
Examining the Evidence: Studies on Chocolate and Weight
Several studies have explored the relationship between chocolate consumption and body weight. Some cross-sectional studies showed that eating chocolate is significantly related to lower BMI. A few studies have shown that eating chocolate is associated with a lower body mass index (BMI). However, these studies were cross-sectional, and thus cannot show cause-and-effect. With these types of studies reverse causality is a common problem: you cannot be sure whether eating chocolate affects one’s weight or vice versa. In fact, the association diminished when researchers excluded participants with preexisting obesity-related illness.
More robust evidence comes from prospective cohort studies and human intervention studies and systematic reviews and meta-analyses summarizing these results. Randomized clinical trials lasting from 2-8 weeks where participants ate 20-50 g of dark chocolate daily did not report any significant changes in weight. However, this might be due to the study duration which was not sufficient to identify changes in weight. Another systematic review and meta-analysis of randomized clinical trials reported no significant effect of cocoa or dark chocolate on body weight, BMI, and waist circumference. However, when analysing a subgroup of participants eating more than 30 g of chocolate per day and a subgroup of trials lasting between 4-8 week, they did show a reduced weight and BMI. Overall, there are conflicting results, indicating that more research is needed.
A study conducted by researchers from the Brigham and the University of Murcia in Spain found that postmenopausal women who consumed 100g of chocolate in the morning or at night did not gain weight despite increasing caloric intake. This suggests that the timing of chocolate consumption might play a role in its impact on weight.
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A meta-analysis of 35 randomized clinical trials investigating the impact of cocoa/dark chocolate on body weight, BMI, and waist circumference did not find any significant effect of cocoa/DC supplementation on these measures. However, subgroup analysis revealed that weight and BMI were reduced with cocoa/DC supplementation ≥ 30 g chocolate per day in trials between 4-8 weeks.
These conflicting results highlight the need for more research to fully understand the relationship between chocolate and weight management.
Building a Healthy Relationship with Chocolate
For many, chocolate cravings are a common experience. A key in reversing the negative effects of these chocolate cravings is to stop making it taboo. You don’t have to feel guilty about craving a food, whether it’s chocolate or broccoli. Instead, try setting some terms of your relationship with chocolate. Savor it and enjoy it with purpose and intention, without the guilt. Don’t sit in front of the TV with your hand in a bottomless bowl of chocolate candies. Instead, be mindful of when and why you are eating it. Having a healthy relationship with all foods is important for your mind and your body.
How to Evaluate Diet and Nutrition News
Given the prevalence of misinformation in the diet and nutrition realm, it's crucial to be a critical consumer of news. Bohannon offers some guidelines for evaluating scientific research behind a story:
- Study Type: Look for information like whether a study was conducted on humans or animals. Human studies are generally more applicable to human health.
- Sample Size: Consider whether a large number of people took part in the study. Larger sample sizes tend to yield more reliable results.
- Measurable Significance: Assess the measurable significance of any effect the researchers claim to find. A statistically significant result doesn't always translate to a practically significant one.
- Peer Review: Check whether the study is published in a respected peer-reviewed journal (although that's not foolproof). Peer review helps ensure the quality and validity of research.
Bohannon advises caution when diet advice seems too good to be true. If some news article seems to be giving you diet advice -- a bold claim like eating this or not eating that is good or bad -- you don't have to read further," Bohannon said. "The scientific consensus has not crystallized around diet and human health outcomes to the degree that you can make any claims yet. This is hard science. I'm afraid to say that the vast majority of reporting in this area -- almost everything you see in glossy magazines devoted to men's and women's health -- is bunk at worst or very, very poorly reported at best."
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