Can Chocolate Help You Lose Weight?

Written by Dr. Steve Chaney on . Posted in Food and Health, Issues, Obesity

A Candy a Day Keeps The Weight Away?

Author: Dr. Stephen Chaney

chocolateSometimes you come across news that just seems too good to be true. The recent headlines saying that you can lose weight just by eating chocolate are a perfect example. Your first reaction when you heard that was probably “Sure, when pigs fly!”

But, it’s such an enticing idea – one might even say a deliciously enticing idea. And, in today’s world enticing ideas like this quickly gain a life of their own. Two popular books have been written on the subject. Chocolate diet plans are springing up right and left. A quick scan of the internet even revealed a web site saying that by investing a mere $1,250 in a training course you could become a “Certified Chocolate Weight Loss Coach” earning $50,000/year.

If you like chocolate as much as most people you are probably wondering could it just possibly be true?

Can Eating Chocolate Help You Lose Weight?

The idea that chocolate could help you lose weight does have some support. There are actually three published clinical studies suggesting that chocolate consumption is associated with lower weight (European Journal of Clinical Nutrition, 62: 247-253, 2008; Nutrition Research, 31: 122-130, 2011; Archives of Internal Medicine, 172: 519-521, 2012).

While that sounds pretty impressive, they were all cross-sectional studies. That means they looked at a cross section of the population and compared chocolate intake with BMI (a measure of obesity). Cross sectional studies have a couple of very important limitations:

1)    Cross sectional studies merely measure associations. They don’t prove cause and effect. Was it the chocolate that caused the lower weight, or was it something else that those populations were doing? We don’t really know.

2)    Cross sectional studies don’t tell us why an association occurs. In many ways this is the old chicken and egg conundrum. Which comes first? In this case the question is whether the people in the studies became obese because they ate less chocolate – or did they eat less chocolate because they were obese and were trying to control their calories? Again, we have no way of knowing.

If Pigs Could Only Fly

If Pigs Could FlyChocolate is relatively rich in fat and high in calories. It’s not your typical diet food. On the surface it seems fairly implausible that eating chocolate could actually help you lose weight.

Scientists love to poke holes in implausible hypotheses, so it is no surprise that a recent study (PLOS ONE, 8(8) e70271) has poked some huge holes in the “chocolate causes weight loss” hypothesis.

This study analyzed data from over 12,000 participants in the Atherosclerosis Risk in Community (ARIC) Study. This was also a cross sectional study, but it was a prospective cross sectional study (That’s just a fancy scientific term which means that the study followed a cross section of the population over time, rather than just asking what that population group looked like at a single time point).

The authors of the study assessed frequency of chocolate intake and weight for each individual in the study at two separate time points 6 years apart. The results were very interesting:

  • When they looked at a cross section of the population at either time point, their results were the same as the previous three studies – namely those who consumed the most chocolate weighed less. So the data are pretty consistent. Overweight people consume less chocolate. But, that still doesn’t tell us why they consume less chocolate.
  • However, when they followed the individuals in the study over 6 years, those who consumed the most chocolate gained the most weight. The chocolate eaters were skinnier than the non-chocolate eaters at the beginning of the study, but they gained more weight as the study progressed. And, the more chocolate they consumed the more weight they gained over the next 6 years. [No surprise here. Calories still count.]
  • When they specifically looked at the population who had developed an obesity related illness between the first and second time point, they found that by the end of the study those participants had:

– Decreased chocolate intake by 37%

– Decreased fat intake by 4.5%

– Increased fruit intake by 20%

– Increased vegetable intake by 17%

  • In short, this study is more consistent with the “obesity causes reduced chocolate intake” model than the “reduced chocolate intake causes obesity” model. Simply put, if you are trying to lose weight, sweets like chocolate are probably among the first things to go.

Of course, even prospective cross sectional studies have their limitations. Double blind, placebo controlled studies are clearly needed to resolve this question. The only published study of this type has reported a slight weight gain associated 25 g/day of dark chocolate, but the study was too small and too short in duration to draw firm conclusions.

In summary, more studies are needed, but the current evidence does not support the “miracle diet food” claims for chocolate.

The Bottom Line:

1)    Pigs still haven’t learned how to fly. As enticing as it may sound, the weight of current evidence does not support the claims that chocolate is a miracle diet food or that eating chocolate every day is a sensible strategy for losing weight.

2)    On the other hand, dark chocolate is probably one of the healthier dessert foods. There is no reason not to enjoy an occasional bite of chocolate as part of a healthy, calorie-controlled diet.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Comments (2)

  • Josephine Dye

    |

    This was very in-lighting. enjoy your news letter.

    Reply

  • Julie Donnelly

    |

    I LOVE chocolate and fortunately Shaklee has the chocolate peanut butter bars so I can get my “fix” and still feel okay about it.

    Reply

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Latest Article

A Low Carb Diet and Weight Loss

Posted January 15, 2019 by Dr. Steve Chaney

Do Low-Carb Diets Help Maintain Weight Loss?

Author: Dr. Stephen Chaney

 

low carb dietTraditional diets have been based on counting calories, but are all calories equal? Low-carb enthusiasts have long claimed that diets high in sugar and refined carbs cause obesity. Their hypothesis is based on the fact that high blood sugar levels cause a spike in insulin levels, and insulin promotes fat storage.

The problem is that there has been scant evidence to support that hypothesis. In fact, a recent meta-analysis of 32 published clinical studies (KD Hall and J Guo, Gastroenterology, 152: 1718-1727, 2017 ) concluded that low-fat diets resulted in a higher metabolic rate and greater fat loss than isocaloric low-carbohydrate diets.

However, low-carb enthusiasts persisted. They argued that the studies included in the meta-analysis were too short to adequately measure the metabolic effects of a low-carb diet. Recently, a study has been published in the British Medical Journal (CB Ebbeling et al, BMJ 2018, 363:k4583 ) that appears to vindicate their position.

Are low carb diets best for long term weight loss?

Low-carb enthusiasts claim the study conclusively shows that low-carb diets are best for losing weight and for keeping it off once you have lost it. They are saying that it is time to shift away from counting calories and from promoting low-fat diets and focus on low-carb diets instead if we wish to solve the obesity epidemic. In this article I will focus on three issues:

  • How good was the study?
  • What were its limitations?
  • Are the claims justified?

 

How Was The Study Designed?

low carb diet studyThe investigators started with 234 overweight adults (30% male, 78% white, average age 40, BMI 32) recruited from the campus of Framingham State University in Massachusetts. All participants were put on a diet that restricted calories to 60% of estimated needs for 10 weeks. The diet consisted of 45% of calories from carbohydrate, 30% from fat, and 25% from protein. [So much for the claim that the study showed low-carb diets were more effective for weight loss. The diet used for the weight loss portion of the diet was not low-carb.]

During the initial phase of the study 161 of the participants achieved 10% weight loss. These participants were randomly divided into 3 groups for the weight maintenance phase of the study.

  • The diet composition of the high-carb group was 60% carbohydrate, 20% fat, and 20% protein.
  • The diet composition of the moderate-carb group was 40% carbohydrate, 40% fat, and 20% protein.
  • The diet composition of the low-carb group was 20% carbohydrate, 60% fat, and 20% protein.

Other important characteristics of the study were:

  • The weight maintenance portion of the study lasted 5 months – much longer than any previous study.
  • All meals were designed by dietitians and prepared by a commercial food service. The meals were either served in a cafeteria or packaged to be taken home by the participants.
  • The caloric content of the meals was individually adjusted on a weekly basis so that weight was kept within a ± 4-pound range during the 5-month maintenance phase.
  • Sugar, saturated fat, and sodium were limited and kept relatively constant among the 3 diets.

120 participants made it through the 5-month maintenance phase.

 

Do Low-Carb Diets Help Maintain Weight Loss?

low carb diet maintain weight lossThe results were striking:

  • The low-carb group burned an additional 278 calories/day compared to the high-carb group and 131 calories/day more than the moderate-carbohydrate group.
  • These differences were even higher for those individuals with higher insulin secretion at the beginning of the maintenance phase of the study.
  • These differences lead the authors to hypothesize that low-carb diets might be more effective for weight maintenance than other diets.

 

What Are The Pros And Cons Of This Study?

low carb diet pros and consThis was a very well-done study. In fact, it is the most ambitious and well-controlled study of its kind. However, like any other clinical study, it has its limitations. It also needs to be repeated.

The pros of the study are obvious. It was a long study and the dietary intake of the participants was tightly controlled.

As for cons, here are the three limitations of the study listed by the authors:

#1: Potential Measurement Error: This section of the paper was a highly technical consideration of the method used to measure energy expenditure. Suffice it to say that the method they used to measure calories burned per day may overestimate calories burned in the low-carb group. That, of course, would invalidate the major findings of the study. It is unlikely, but it is why the study needs to be repeated using a different measure of energy expenditure.

#2: Compliance: Although the participants were provided with all their meals, there was no way of being sure they ate them. There was also no way of knowing whether they may have eaten other foods in addition to the food they were provided. Again, this is unlikely, but cannot be eliminated from consideration.

#3: Generalizability: This is simply an acknowledgement that the greatest strength of this study is also its greatest weakness. The authors acknowledged that their study was conducted in such a tightly controlled manner it is difficult to translate their findings to the real world. For example:

  • Sugar and saturated fat were restricted and were at very similar levels in all 3 diets. In the real world, people consuming a high-carb diet are likely to consume more sugar than people in the other diet groups. Similarly, people consuming the low-carb diet are likely to consume more saturated fat than people in the other diet groups.
  • Weight was kept constant in the weight maintenance phase by constantly adjusting caloric intake. Unfortunately, this seldom happens in the real world. Most people gain weight once they go off their diet – and this is just as true with low-carb diets as with other diets.
  • The participants had access to dietitian-designed prepared meals 3 times a day for 5 months. This almost never happens in the real world. The authors said “…these results [their data] must be reconciled with the long-term weight loss trials relying on nutrition education and behavioral counseling that find only a small advantage for low carbohydrate compared with low fat diets according to several recent meta-analyses.” [I would add that in the real world, people do not even have access to nutritional education and behavioral modification.]

 

low carb diet and youWhat Does This Study Mean For You?

  • This study shows that under very tightly controlled conditions (dietitian-prepared meals, sugar and saturated fat limited to healthy levels, calories continually adjusted so that weight remains constant) a low-carb diet burns more calories per day than a moderate-carb or high-carb diet. These findings show that it is theoretically possible to increase your metabolic weight and successfully maintain a healthy weight on a low-carb diet. These are the headlines you probably saw. However, a careful reading of the study provides a much more nuanced viewpoint. For example, the fact that the study conditions were so tightly controlled makes it difficult to translate these findings to the real world.
  • In fact, the authors of the study acknowledged that multiple clinical studies show this almost never happens in the real world. These studies show that most people regain the weight they have lost on low-carb diets. More importantly, the rate of weight regain is virtually identical on low-carb and low-fat diets. Consequently, the authors of the current study concluded “…translation [of their results to the real world] requires exploration in future mechanistic oriented research.” Simply put, the authors are saying that more research is needed to provide a mechanistic explanation for this discrepancy before one can make recommendations that are relevant to weight loss and weight maintenance in the real world.
  • The authors also discussed the results of their study in light of a recent, well-designed 12-month study (CD Gardener et al, JAMA, 319: 667-669, 2018 ) that showed no difference in weight change between a healthy low-fat versus a healthy low-carbohydrate diet. That study also reported that the results were unaffected by insulin secretion at baseline. The authors of the current study noted that “…[in the previous study] participants were instructed to minimize or eliminate refined grains and added sugars and maximize intake of vegetables. Probably for this reason, the reported glycemic load [effect of the diet on blood sugar levels] of the low-fat diet was very low…and similar to [the low-carb diet].” In short, the authors of the current study were acknowledging that diets which focus on healthy, plant-based carbohydrates and eliminate sugar, refined grains, and processed foods may be as effective as low-carb diets for helping maintain a healthy weight.
  • This would also be consistent with previous studies showing that primarily plant-based, low-carb diets are more effective at maintaining a healthy weight and better health outcomes long-term than the typical American version of the low-fat diet, which is high in sugar and refined grains. In contrast, meat-based, low-carb diets are no more effective than the American version of the low-fat diet at preventing weight gain and poor health outcomes. I have covered these studies in detail in my book “Slaying The Food Myths.”

Consequently, the lead author of the most recent study has said: “The findings [of this study] do not impugn whole fruits, beans and other unprocessed carbohydrates. Rather, the study suggests that reducing foods with added sugar, flour, and other refined carbohydrates could help people maintain weight loss….” This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.

The Bottom Line

 

  • A recent study compared the calories burned per day on a low-carb, moderate-carb, and high-carb diet. The study concluded that the low-carb diet burned significantly more calories per day than the other two diets and might be suitable for long-term weight control. If confirmed by subsequent studies, this would be the first real evidence that low-carb diets are superior for maintaining a healthy weight.
  • However, the study has some major limitations. For example, it used a methodology that may overestimate the benefits of a low-carb diet, and it was performed under tightly controlled conditions that can never be duplicated in the real world. As acknowledged by the authors, this study is also contradicted by multiple previous studies. Further studies will be required to confirm the results of this study and show how it can be applied in the real world.
  • In addition, the kind of carbohydrate in the diet is every bit as important as the amount of carbohydrate. The authors acknowledge that the differences seen in their study apply mainly to carbohydrates from sugar, refined grains, and processed foods. They advocate diets with low glycemic load (small effects on blood sugar and insulin levels) and acknowledge this can also be achieved by incorporating low-glycemic load, plant-based carbohydrates into your diet. This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.
  • Finally, clinical studies report averages, but none of us are average. When you examine the data from the current study, it is evident that some participants burned more calories per hour on the high-carb diet than other participants did on the low carb diet. That reinforces the observation that some people lose weight more effectively on low-carb diets while others lose weight more effectively on low-fat diets. If you are someone who does better on a low-carb diet, the best available evidence suggests you will have better long-term health outcomes on a primarily plant-based, low-carb diet such as the low-carb version of the Mediterranean diet.

For more details read the article above.

 

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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