A person could have whiplash following nutrition in the news recently. In less than one week’s time, hundreds of news stories and Twitter posts have been careening back and forth between discussion of a study linking chocolate with a healthier weight and a television broadcast linking sweets with a wide array of health problems.
Coupled with reports from presentations at a major cancer research conference reminding us that weight control is one of the most important steps we can take to reduce our cancer risk, you may be wondering what on earth to make of all this.
Is chocolate a help or a hindrance to health? Does it really pose no barrier to a healthy weight? For me, the answers lie in the study details that you don’t get from looking only at the headlines.
Do sweets cause cancer?
You may have heard that “sugar feeds cancer”. It is true that growth of cancer cells is fueled by sugar.
But let’s be clear that this is sugar circulating in the blood, which is fuel to all our cells. Even if you ate no sugar – even no carbohydrates at all — you would still have sugar circulating in your blood. When blood sugar dips low, body processes in the liver and muscles automatically switch on to produce blood sugar from sources such as protein and glycogen. Years ago, people with diabetes were told to avoid all sugar. Today, we have many studies showing that sugar consumption alone does not drive blood sugar levels.
In a healthy person, as soon as carbohydrate is eaten (before it’s even been absorbed from the gut), we are beginning to get insulin ready to handle the rise in blood sugar that’s coming. Studies that involve large amounts of sugar consumed all on their own may have implications for people who are guzzling gigantic bottles of regular soda all day. But normally when we consume sugar, especially if it’s part of a meal with fiber-containing food, the resulting rise in blood sugar is moderate and brought back to normal relatively quickly.
The role of insulin is a super-hot field in cancer research today. Beside insulin’s role in helping sugar move from the blood into cells where it is used, insulin also promotes growth and reproduction of normal cells and, yes, cancer cells.
“Insulin resistance” is a growing problem occurring in association with overweight and sedentary lives. As I wrote in last week’s post on Diabetes & Cancer, insulin resistance means that when blood sugars rise, despite plenty of insulin, cells are unable to use it. As a result, blood sugars continue to rise and the pancreas pumps out more and more insulin. We need further research about the impact of excessively high blood sugars, but overall, research suggests that high levels of insulin are a far clearer concern.
We reduce insulin resistance by reaching and maintaining a healthy weight and keeping active. A balanced diet focused around vegetables, fruits, whole grains and beans supplies dietary fiber that slows blood sugar rise and provides antioxidants that help avoid chronic low-grade inflammation that can lead to insulin resistance.
Chocolate & a healthy weight
A widely publicized study that showed no link between frequency of chocolate consumption and weight has raised all kinds of questions about whether phytochemicals in chocolate might mean that calories from chocolate don’t impact weight the same as calories from other sources. Contrary to some commentaries on this study that you may see, the researchers did analyze chocolate’s link to weight both with and without adjusting for overall calorie consumption. Either way, eating chocolate more often was linked with lower weight.
Before you make the jump of concluding that chocolate poses no problem for weight management, a few details do need attention:
√ Although analysis adjusted for how often subjects engaged in vigorous activity, there was no adjustment for moderate activity. Moderate activity includes things like a brisk walk, gardening and many other options that are far more common among most adults than vigorous activity, and it plays an important role in long-term weight control.
√ Amount of chocolate eaten – how many ounces per week – was not related to being overweight. Authors of the study did not include this information in the abstract of the study, but it’s there in the overall results. In contrast to the “so chocolate might help weight loss” argument, if anything, this suggests that chocolate consumption itself neither helped nor hindered a healthy weight.
√ This is an observational study, not a controlled trial. It doesn’t show the effect of chocolate on weight; it could just as well be that leaner people give themselves “permission” to have a small amount of chocolate more often than do obese people.
√ Note that this is about “chocolate” as a candy, not chocolate in the many forms we consume it, such as chocolate donuts and chocolate cake. We’ll come back to this important point.
√ A problem for this and all studies comparing what people say about their eating and some outcome like weight is that people aren’t accurate about what they eat. What’s more, it’s widely documented in research that the more overweight someone is, the more they underestimate how much they eat – sometimes by 40% or more – and this is particularly true for a food that might be considered “bad” or high-calorie. Whatever the reason, this could be especially problematic for something like chocolate, often eaten in situations in which we are not paying attention to our eating.
Chocolate for Antioxidants?
Chocolate contains natural compounds called flavonoids that show powerful antioxidant effects in laboratory studies. They are from the same family of compounds that includes health-protective compounds like the resveratrol in grape juice and EGCG in green tea. So what’s the evidence about chocolate’s impact on overall health?
*Reduction in heart disease risk of 24 to 37 percent compared to those who rarely or never eat chocolate is reported in several human studies. Chocolate consumption decreases LDL (“bad”) cholesterol and increases flow through blood vessels. It also slows the oxidation of LDL cholesterol to a form more damaging to blood vessels.
*Reduced blood pressure is linked with long-term consumption of small amounts of chocolate. An analysis of 13 different short-term randomized trials shows that chocolate or cocoa, especially in forms rich in flavonoid compounds, can reduce elevated blood pressure several points.
*Reduced markers of inflammation, such as CRP, are seen in limited population studies. For example, among healthy Italian adults, consumers of dark chocolate showed 10 percent lower levels of CRP than those who did not eat chocolate. Note the catch: this effect was seen with one small serving (less than an ounce) about every three days. In this study, those who ate more than about 1½ ounces per week had no lower levels of CRP than those who ate no chocolate. However, in a controlled trial, cocoa powder decreased other markers of inflammation, but the amounts translate to amounts of chocolate likely too large to fit into an overall healthy diet; we don’t know whether long-term use of more moderate amounts might have equal impact.
*Impact on overall circulating antioxidants is uncertain. One study comparing total antioxidant activity from single servings of cocoa, green tea, black tea and red wine, reported cocoa markedly higher than the rest. However, according to an analysis of 19 controlled intervention trials, although cocoa products decrease LDL cholesterol oxidation, they do not necessarily affect blood measures of overall antioxidant defense. We need more research to identify what factors in the chocolate product, diet or individual might affect chocolate’s overall antioxidant impact.
Practical Points on Chocolate Choice
The flavonoid content of chocolate is highly variable. Dark chocolate, usually 60 to 85 percent cocoa (which includes cocoa bean solids plus cocoa butter), is higher in flavonoids and has a more intense flavor. It is less sweet, because as cocoa content goes up, sugar content drops. Milk chocolate can range from 7 to 50 percent cocoa, so flavonoid content is lower. White chocolate contains no cocoa bean solids (and therefore is not a source of flavonoids).
The fat content of chocolate is not the problem that some people consider it to be. Seventy percent of chocolate’s fat is either monounsaturated or a particular type of saturated fat called stearic acid that does not raise blood cholesterol. Both dark and milk chocolate are heart healthy options, especially if they are replacing other sweets.
Research suggests health benefits from drinking cocoa, too. However, most widely available cocoa mixes contain cocoa treated with alkali to produce a richer taste. Unfortunately, this “Dutch cocoa” is substantially lower in antioxidants. Gourmet cocoa mixes are available made with natural (untreated) cocoa. You can also make a flavonoid-rich cup of cocoa with natural cocoa from the grocery store plus your own sweetener and milk.
So we’re back to the impact of a chocolate fix on your weight….
- One ounce of dark chocolate (1/3 to ¼ of a 3- or 4-oz bar, or 4 small pieces) 135-165 calories
- One ounce of milk chocolate (1/4 of a 4-oz bar or 4 small pieces) 150 to 165 calories
- One tablespoon of natural cocoa 20 calories; combined with varying proportions of nonfat milk and water with a little sugar or non-calorie sweetener makes a cup of cocoa to savor for 50 to 130 calories
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- Dunkin’ Donuts chocolate donut 370 calories
- Five Oreo cookies 265 calories
- A third of the package of Oreo cookies (don’t think nobody does that!) 690 calories
- 1 cup Ben & Jerry’s chocolate fudge brownie ice cream 520 calories
- Starbucks Venti Caffè Mocha with whipped cream 410 calories
Chocolate doesn’t replace vegetables and fruits. Flavonoid content of vegetables and fruits such as spinach, garlic, raisins and oranges can be 8 to 16 times higher per serving than even dark chocolate. And we get those health-promoting phytochemicals in a serving of fruits and vegetables for 25 to 80 calories, and in tea for no calories at all.
With overall smart food choices, most adults can maintain a healthy weight while consuming 120 to 350 calories a day from foods that don’t add much nutritionally. Flavonoid-rich chocolate and cocoa could be great ways to “spend” those calories instead of foods that are negative influences on health, such as doughnuts or regular soft drinks. Savor small portions of chocolate itself that provide flavonoid benefits, not chocolate cakes and pastries that are loaded with extra calories, sugar and unhealthful fats.
Bottom line: Whether you’re concerned about weight or overall health, it looks like modest chocolate consumption a few times a week or so is not a barrier, and could even be healthful. Don’t assume, however, that “more is better” applies here.
Let’s talk: What does chocolate in moderation look like for you?
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