Is Diet Soda Bad For You?

Written by Dr. Steve Chaney on . Posted in Diet Soda and Health

Do Diet Sodas Increase Your Risk Of Stroke?

Author: Dr. Stephen Chaney

diet soda badIs diet soda bad for you?  With over two third of Americans overweight or obese, it is clear that we are in a midst of an obesity epidemic. Multiple studies have shown that over consumption of sugar-sweetened beverages (soft drinks, energy drinks, and “fruit” juices that aren’t made from real fruit) are major drivers of the obesity epidemic. Because of these trends, many experts recommend substituting artificially sweetened beverages for sugar-sweetened beverages in the American diet.

Is that advice sound? Do diet sodas help prevent weight gain? Are they safe? The answers to those questions are not as clear as you might expect.

Do Diet Sodas Prevent Weight Gain?

diet soda make you fatThe answer to that question would seem to be a no-brainer. Substituting beverages with no calories for beverages with calories should lead to less weight gain. However, as I summarized in a previous “Health Tips From the Professor” article Do Diet Sodas Make You Fat, the answer is not clear at all. Some studies suggest that diet sodas help people lose weight. Other studies suggest diet sodas cause just as much weight gain as sugar-sweetened sodas.

With so much confusion in the literature, what should we believe? More importantly, what do the experts say? This January an international consortium of experts reviewed all of the pertinent literature and published a position paper on whether artificially sweetened beverages were of value in responding to the global obesity crisis (Borges et al, PLOS Medicine, DOI: 10.1371/journal.pmed.1002195).

These authors concluded:

  • “In summary, the available evidence…does not consistently demonstrate that artificially-sweetened beverages are effective for weight loss or preventing metabolic abnormalities [pre-diabetes and diabetes]. Evidence on the impact of artificially-sweetened beverages on child health is even more limited and inconclusive than in adults.”
  • “The absence of evidence to support the role of artificially sweetened beverages in preventing weight gain and the lack of studies on their long-term effects on health strengthen the position that artificially-sweetened beverages should not be promoted as part of a healthy diet.”

Is Diet Soda Bad For You?

diet soda strokeAs if the lack of proven efficacy weren’t bad enough, other studies suggest that diet sodas may also be bad for your health. In previous issues of “Health Tips From the Professor,” I have discussed other studies showing that diet sodas are just as likely as regular sodas to increase risk of diabetes Artificial Sweeteners and Diabetes and heart disease Soft Drinks and Heart Disease.

Even worse, a study published earlier this month (Pase et al, Stroke, DOI: 10.1161/STROKE.AHA.116.016027 ) concluded that diet sodas may significantly increase the risk of stroke and Alzheimer’s disease.

This study looked at 2888 participants of the Framingham Heart Study. The participants evaluated for risk of stroke had a mean age of 62 on enrollment. Those evaluated for risk of dementia had a mean age of 69 on enrollment. All subjects were followed for 10 years. Three food frequency questionnaires were administered during that 10-year period to evaluate consumption of diet and sugar-sweetened sodas. The results of the study were:

  • People consuming at least one diet soda per day over a 10-year period were 3X more likely to have a stroke or develop dementia (primarily Alzheimer’s disease) than people consuming no diet sodas.
  • No increased risk of stroke or dementia was seen for people consuming sugar-sweetened beverages. However, that does not mean that sugar-sweetened beverages are good for you. Previous studies have shown they increase the risk of obesity and diabetes.
  • When the data were corrected for hypertension, cardiovascular disease, and obesity (waist to hip ratio), diet sodas still increased the risk of having a stroke by 2.6-fold.
  • This is not the only study to show a link between diet sodas and stroke. Two other studies have come to the same conclusion, and in both of those studies the increased risk was also seen only with diet soda consumption, not with sugar-sweetened soda consumption.

The author of the study concluded by saying: “As the consumption of artificially sweetened soft drinks is increasing in our community, along with the prevalence of stroke and dementia, future research is needed to replicate our findings and to investigate the mechanisms underlying the reported association.”

I agree. Current evidence does not definitively prove that diet sodas cause stroke and Alzheimer’s, but these are life-changing adverse health outcomes. Further research to test this association is desperately needed to know whether or not diet soda is bad for you.

Are Diet Sodas Safe and Effective?

diet soda dangerousAs you might expect these studies have caused quite a bit of controversy. Some experts have embraced these studies and have concluded that health professionals should stop recommending diet sodas as a safe and effective alternative to sugar-sweetened sodas.
Others have been unwilling to change their recommendation of diet sodas for people who are obese and/or diabetic. Their rationale is 3-fold:

  • These studies merely show that diet soda consumption is associated with weight gain, diabetes, heart disease, stroke and Alzheimer’s. Association does not prove causation, so their viewpoint is that there is no conclusive proof that diet sodas cause weight gain and health risks.
  • The obesity epidemic is a major health crisis, and consumption of sugar-sweetened beverages plays an important role in weight gain.
  • They are convinced that most people are so addicted to the sweet taste of sugar that they would be unwilling to switch to calorie free options like water or herbal teas.

In short, they are desperately clinging to the hope that substituting diet sodas for sugar-sweetened sodas will put a dent in the obesity crises because they don’t believe there are any other viable options.

What Do These Studies Mean For You?

I side with those experts who have looked at the data from the opposite perspective and concluded there is no convincing evidence that diet sodas are either safe or effective.

If the conversation were just centered around weight gain, diabetes, and heart disease, this could be considered an academic discussion. One could argue that diet sodas might have some benefit, and, at the worst, would have the same health risks as the regular sodas they replaced.

However, the possibility that diet sodas may increase the risk of stroke and dementia is a game-changer in my mind. That’s because consumption of sugar-sweetened sodas does not appear to increase the risk of either stroke or dementia. If true, that means that substitution of diet sodas for sugar-sweetened sodas is not a neutral substitution. It could cause serious harm.

With no good evidence that diet sodas help people control weight and the possibility that they may have serious health risks, it is difficult to see how anyone in good conscience can continue to recommend diet sodas in place of regular sodas.

My recommendation is to substitute water and other unsweetened beverages for the sugar sweetened beverages you are currently consuming. If you crave the fizz of sodas, drink carbonated water. If you need more taste, try herbal teas or infuse water with slices of lemon, lime, or your favorite fruit. If you buy commercial brands of flavored water, check the labels carefully. They may contain sugars or artificial sweeteners. Those you want to avoid.

So, is diet soda bad for you?  Well, it’s not good for you.

The Bottom Line

  • This January an international consortium of experts reviewed all of the pertinent literature and concluded: “The available evidence…does not consistently demonstrate that artificially-sweetened beverages are effective for weight loss or preventing metabolic abnormalities. The absence of evidence to support the role of artificially sweetened beverages in preventing weight gain and the lack of studies on other long-term effects on health strengthen the position that artificially-sweetened beverages should not be promoted as part of a healthy diet.”
  • This April a study was published reporting that people consuming at least one diet soda per day over a 10-year period were 3X more likely to have a stroke or develop dementia (primarily Alzheimer’s disease) than people consuming no diet sodas. Two other studies on the effect of diet sodas on the risk of stroke have come to similar conclusions.
  • We cannot yet say definitively that diet sodas cause stroke and dementia. Further research is clearly needed to test these associations. However, at this point it is safe to say there is no convincing evidence that diet sodas are either safe or effective.
  • With no good evidence that diet sodas help people control weight and the possibility that they may have serious health risks, it is difficult to see how anyone in good conscience can continue to recommend diet sodas as a substitute for sugar-sweetened sodas.
  • My recommendation is to substitute water and other unsweetened beverages for the sugar sweetened beverages you are currently consuming. If you crave the fizz of sodas, drink carbonated water. If you need more taste, try herbal teas or infuse water with slices of lemon, lime, or your favorite fruit. If you buy commercial brands of flavored water, check the labels carefully. They may contain sugars or artificial sweeteners. Those you want to avoid.
  • For a more nuanced discussion of this issue, 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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Latest Article

Does Protein Supplement Timing Matter?

Posted May 15, 2018 by Dr. Steve Chaney

How Do You Gain Muscle Mass & Lose Fat Mass?

Author: Dr. Stephen Chaney

 

protein supplement timingMost of what you read about protein supplements on the internet is wrong. That is because most published studies on protein supplements:

  • Are very small
  • Are not double blinded.
    • Both the subjects and the investigators knew who got the protein supplement.
  • Are done by individual companies with their product.
    • You have no idea which ingredients are in their product are responsible for the effects they report.
    • You have no idea how their product compares with other protein products.
    • There is no standardization with respect to the amount or type of protein or the addition of non-protein ingredients.

Because of these limitations there is a lot of misleading information on the benefits of protein supplements timing and maximal benefit. Let’s start by looking at why people use protein supplements. Let’s also look at what is generally accepted as true with respect to the best supplement timing.

There are 4 major reasons people consume protein supplements:

  • Enhance the muscle gain associated with resistance training: In this case, protein supplements are customarily consumed concurrently with the workout.
  • Preserve muscle and accelerate fat loss while on a weight loss diet: In this case, protein supplements are customarily consumed with meals or as meal replacements.
  • Provide a healthier protein source. In this case, protein supplements are customarily consumed with meals in place of meat protein.
  • Prevent muscle loss associated with aging or illness. There is no customary pattern associated with this use of protein supplements.

How good are the data supporting the customary timing of protein supplementation? The answer is: Not very good. The timing is based on a collection of weak studies which do not always agree with each other.

The current study  (J.L. Hudson et al, Nutrition Reviews, 76: 461-468, 2018 ) was designed to fill this void in our knowledge. It is a meta-analysis that compares all reasonably good studies that have looked at the effect of protein supplement timing on weight gain or loss, lean muscle mass gain, fat loss, and the ratio of lean muscle mass to fat mass.

How Was The Study Done?

The authors started by doing a literature search of all studies that met the following criteria:

  • The study was a randomized control trial with parallel design. This means that study contained a control group. It does not mean that the investigators or subjects were blinded with respect to which subjects used a protein supplement and which did not.
  • The subjects were engaged in resistance training.
  • The study lasted 6 weeks or longer.
  • Reliable methods were used to measure body composition (lean muscle mass and fat mass).
  • The subjects were healthy and at least 19 years old.
  • There was no restriction on the food the subjects consumed.

The authors started with 2074 published studies and ended up with 34 that met all their criteria. They then separated the studies into two groups – those in which the protein supplements were used with meals and those in which the protein supplements were used between meals.

Both groups were diverse.

  • Group 1 included subjects who consumed their protein supplement with their meal and those who consumed their protein supplement as a meal replacement.
  • Group 2 included subjects who consumed their protein supplement concurrent with exercise (usually immediately after exercise) and those who consumed their protein supplement at a fixed time of day not associated with exercise.

Does Protein Supplement Timing Matter?

 

protein supplement timing workoutsBecause the individual studies were very diverse in the way they were designed, the authors could not calculate a reliable estimate of how much lean muscle mass was increased or fat mass was decreased. Instead, they calculated the percentage of studies showing an increase in lean muscle mass or a decrease in fat mass.

When the authors compared protein supplements consumed with meals versus protein supplements consumed between meals:

  • Weight gain was observed in 56% of the studies of protein supplementation with meals compared to 72% of the studies of protein supplementation between meals. In other words, protein supplements consumed with meals were less likely to lead to weight gain than protein supplements consumed between meals.
  • An increase in lean muscle mass was observed in 94% of the studies of protein supplementation with meals compared to 90% of the studies of protein supplementation between meals. In other words, timing of protein supplementation did not matter with respect to increase in muscle mass.
  • A loss of fat mass was observed in 87% of the studies of protein supplementation with meals compared to 59% of the studies of protein supplementation between meals. In other words, protein supplements consumed with meals were more likely to lead to loss of fat mass.
  • An increase in the ratio of lean muscle mass to fat mass was observed in 100% of the studies of protein supplementation with meals compared to 87% of the studies of protein supplementation between meals. In short, protein supplements consumed with meals were slightly more likely to lead to an increase in the ratio of lean muscle mass to fat mass.

The following seem to suggest protein supplement timing matters:

The authors pointed out that their findings were consistent with previous studies showing that when protein supplements are consumed with a meal they displace some of the calories that otherwise would have been consumed. Simply put, people naturally compensate by eating less of other foods.

In contrast, the authors stated that previous studies have shown that when foods, especially liquid foods, are consumed as snacks (between meals), people are less likely to compensate by reducing the calories consumed in the next meal.

The others concluded: “Concurrently with resistance training, consuming protein supplements with meals, rather than between meals, may more effectively promote weight control and reduce fat mass without influencing improvements in lean [muscle] mass.”

What Are The Limitations Of The Study?

Meta-analyses such as this one, are only as good as the studies included in the meta-analysis. Unfortunately, most sports nutrition studies are very weak studies. Thus, this meta-analysis is a perfect example of the “Garbage In: Garbage Out (GI:GO)” phenomenon.

For example, let’s start by looking at what the term “protein supplement” meant.

  • Because the studies were done by individual companies with their product, the protein supplements in this meta-analysis:
    • Included whey, casein, soy, bovine colostrum, rice or combinations of protein sources.
    • Were isolates, concentrates, or hydrolysates.
    • Contained various additions like creatine, amino acids, and carbohydrate.
  • As I discuss in my book, Slaying the Food Myths, previous studies have shown that optimal protein and leucine levels are needed to maximize the increase in muscle mass and decrease in fat mass associated with resistance exercise. However, neither protein nor leucine levels were standardized in the protein supplements included in this meta-analysis.
  • Previous studies have shown that protein supplements that have little effect on blood sugar levels (have a low glycemic index) are more likely to curb appetite. However, glycemic index was not standardized for the protein supplements included in this meta-analysis.

protein supplement timing workout peopleIn short, the conclusions of this study might be true for some protein supplements, but not for others. We have no way of knowing.

We also need to consider the composition of the two groups.

  • Protein supplements used as meal replacements are more likely to decrease weight and fat mass than protein supplements consumed with meals. Yet, both were included in group 1.
  • Some studies suggest that protein supplements consumed concurrent with resistance exercise are more likely to increase muscle mass than protein supplements consumed another time of day. Yet, both are included in group 2. We also have no idea whether the meals with protein supplements in group 1 were consumed shortly after exercise or at an entirely different time of day.

This was the most glaring weakness of the study because it was completely avoidable. The authors could have grouped the studies into categories that made more sense.

In other words, there are multiple weaknesses that limit the predictive power of this study.

What Can We Learn From This Study?

Despite its many limitations, this study does remind us that protein supplements do have calories. This is of relatively little importance for people whose primary goal is to increase lean muscle mass.

However, most of us are using protein supplements to lose weight or to increase our lean mass to fat mass ratio. Simply put, we are either trying to lean out (shape up) or lose weight. And, we want to lose that weight primarily by getting rid of excess fat. For us, calories do matter. With that in mind:

  • If we are consuming a protein supplement immediately after exercise or between meals we probably should make a conscious effort to reduce our daily caloric intake elsewhere in our diet.
  • Alternatively, we could consume the protein supplement with a meal, but time the meal so it occurs shortly after exercise.

 

The Bottom Line:

 

A recent study looked at the optimal timing of protein supplements consumed by subjects who were engaged in resistance exercise. Specifically, the study compared protein supplements consumed with meals versus protein supplements consumed between meals on weight, lean muscle mass, fat mass, and the ratio of lean muscle mass to fat mass. The study reported:

  • Protein supplements consumed with meals were less likely to lead to weight gain than protein supplements consumed between meals.
  • Timing of protein supplementation did not matter with respect to increase in muscle mass.
  • Protein supplements consumed with meals were more likely to lead to loss of fat mass.
  • Protein supplements consumed with meals were slightly more likely to lead to an increase in the ratio of lean mass to fat mass.

The authors pointed out that their findings were consistent with previous studies showing that when a protein supplement was consumed with a meal it displaces some of the calories that would have been otherwise consumed. Simply put, people naturally compensate by eating less of other foods.

In contrast, the authors said that previous studies have shown that when foods, especially liquid foods, are consumed as snacks (between meals), people are less likely to compensate by reducing the calories consumed in the next meal.

As discussed in the article above, the study has major weaknesses. However, despite its many weaknesses, this study does remind us that protein supplements do have calories. This is of relatively little importance for people whose primary goal is to increase lean muscle mass.

However, for those of us who are using protein supplements to lose weight or to increase our lean mass to fat mass ratio, calories do matter.  With that in mind:

  • If we are consuming a protein supplement immediately after exercise or between meals we probably should make a conscious effort to reduce our daily caloric intake elsewhere in our diet.
  • Alternatively, we could consume the protein supplement with a meal, but time the meal so it occurs shortly after exercise.

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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