Does Sugar Cause Heart Disease?

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

Is Sugar No Longer Your Best Friend?

Author: Dr. Stephen Chaney

SugarSugar has gotten a lot of bad press in recent years. You’ve probably already heard that high sugar intake is associated with inflammation, obesity and diabetes. As if that weren’t bad enough, the latest headlines proclaim that added sugar may also increase our risk of fatal heart disease. Are those headlines true? And if they are true, what should you do about it?

Sugar Basics – The Truth About Sugar

There are three facts about sugar that almost every expert agrees with:

  • The sugars that occur naturally in foods like fruits and vegetables are generally not a problem unless you are a diabetic. It is the added sugars in our diet that we should be concerned with.
  • The amount of added sugars in the American diet has increased dramatically since the founding of this country. Based on data from the US Department of Commerce and the USDA, the amount of added sugar in the American diet has gone from 6.3 pounds/year in 1822 to over 100 pounds/year in 2000. Put another way, we have gone from consuming the amount of sugar in a 12 oz soda every 5 days in 1822 to every 7 hours in 2000.
  • The lion’s share of that added sugar is coming from sodas and similar sugary beverages. The amounts are: sodas and other sugar-sweetened beverages (37.1%), grain-based desserts (13.7%), fruit drinks (8.9%), dairy desserts (6.1%) and candy (5.8%).

Beyond that there is little agreement among experts. When I was a young man the sugar “villains” were glucose and sucrose. Then it was sugar alcohols. Today it is high-fructose corn syrup and maltodextrin. Tomorrow it will be something else.

In reality there are no sugar heroes and no sugar villains. The harmful effects of added sugars are based almost entirely on:

  • The amount of added sugars in the diet…and…
  • The type of foods those added sugars are found in.

For more information, watch my video “The Truth About Sugar”.

Does Sugar Cause Heart Disease?

The study behind the headlines (Yang et al, JAMA Internal Medicine, 174: 516-524, 2014) followed 11,733 participants in the 3rd National Health And Nutrition Examination Survey (NHANES III) for an average of 14.6 years. (NHANES studies are designed to represent a cross section of the adult US population). Sugar intake was based on the average of two dietary surveys for most of the participants, and cardiovascular deaths were determined from the NHANES III Linked Mortality Files.

The average intake of added sugar in the American population was around 16% of total calories (compared to around 1% of total calories in 1822). For comparison purposes, the authors divided the population into three groups based on added sugar consumption:

  • Those consuming less than 10% of calories from added sugar (28.6% of the population).
  • Those consuming between 10% and 25% of calories from added sugars (46.4% of the population).
  • Those consuming more than 25% of calories from added sugars (25.0% of the population).

When the groups with the 10-25% and >25% of calories from added sugars were compared to the <10% group with respect to cardiovascular deaths, the results were pretty striking.

  • The group consuming 10-25% of calories from added sugars had a 30% increased risk of dying from heart disease
  • And the group consuming >25% of calories from added sugars had a 275% increased risk of dying from heart disease!

This association between added sugar consumption and risk of cardiovascular death was independent of age, sex, race/ethnicity, educational attainment, physical activity, HEI score (a measure of overall diet quality and BMI (a measure of obesity).

The Strengths And Weaknesses of This Study

Strengths:

  • This was a particularly large, well designed study.
  • This study is consistent with a number of early studies suggesting that added sugar intake increases the risk of cardiovascular death. See, for example “Can Soft Drinks Cause Heart Disease?

Weaknesses:

  • The main weakness of this study is that it measures associations only. It does not prove cause and effect.

Should You Switch To Diet Sodas?

Diet SodaYou may be thinking that you should switch to diet sodas – and perhaps artificially sweetened snacks and desserts as well. It only makes sense that if sugar is the problem, artificial sweeteners must be the answer. Wrong! The latest research suggests that diet sodas may be just as bad as the sugar-sweetened sodas.

I have already shared one study with you that linked consumption of diet sodas with increased risk of heart disease (see “Can Soft Drinks Cause Heart Disease?”). The link between diet sodas and heart disease has now been supported by another major clinical study reported by Dr. Ankur Vyas from University of Iowa, March 30, 2014 at the American College of Cardiology’s 63rd Annual Scientific Session.

This study followed 60,000 women with an average age of 62.8 years who were enrolled in the Woman’s Health Initiative Observational Study for 9 years. They reported that compared to women who never or rarely drank diet sodas, those who consumed two or more diet sodas/day were:

  • 30% more likely to suffer heart attacks and strokes…and…
  • 50% more likely to die from cardiovascular disease.

What Can You Drink?

By now you are probably asking yourself: “If regular sodas, diet sodas, other sugary and diet beverages, and even most fruit juices are out, what else can I drink? Is there anything left?”

It’s not quite as daunting as it seems at first. It may take some time to re-educate your taste buds, but your health is worth it. Here are some healthy alternatives:

  • My #1 recommendation is always water. If you crave some flavor, add lemon, mint, or your favorite fruits. Herbal teas are another flavorful, healthy choice.
  • If you crave caffeine, go for green tea, regular tea or coffee – without sweeteners, of course.
  • If you crave the carbonation, start with unsweetened mineral water or seltzer and add you favorite flavorings.

The Bottom Line:

1)    The evidence is getting stronger every day that too much added sugar in our diet is linked to increased risk of death from cardiovascular disease. If you are consuming >25% of calories from added sugars the increased risk is almost 3-fold!

2)    The evidence from this study suggests that it would be prudent to keep added sugars below 10% of calories. For most Americans this represents around 200 calories/day from added sugars. That compares with the World Health Organization’s recommendation that added sugars be <10% of calories, the Institute of Medicine’s recommendation that added sugars be <25% of calories, and the American Heart Association’s recommendation that added sugars be <100 calories for women and <150 calories for men.

3)    There are no sugar heroes and villains. The amount of added sugar in the diet is much more important than the kind of sugar. The food that the sugar is found in is also very important, with sodas and similar sugar-sweetened beverages being the worst offenders (See my video “The Truth About Sugar” for more information).

4)    Artificial sweeteners are not the solution. A recent study with postmenopausal women suggests that consumption of as few as two diet sodas a day increases the risk of heart attacks and strokes by 30% and cardiovascular death by 50%.

5)    Don’t despair. You won’t have to go thirsty. There are lots of healthy alternatives available (see 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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Comments (3)

  • Mary Sue Whatley

    |

    The Lord Jesus Christ let me know several years ago that ‘sugar’ is a destroyer.

    I know that there are some good sugars, such as honey, xylitol, etc., but He was referring to the white sugar that most people use.

    Reply

  • Pearlene

    |

    Good way of explaining, and good post to take information concerning my presentation topic, which i am going
    to deliver in university.

    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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