The Diet Soda Delusion – The Epiphenomenon of Obesity V
By Jason Fung, MD
Replacing a regular sugared drink with diet sodas seems like a good way to lose weight. Diet drinks have zero calories and no sugar. Since this will lower sugar intake, it seems like a good idea. Both the American Diabetes Association and the American Heart Association in 2012 endorsed the use of diet drinks as a way of losing weight and improving health. The evidence for benefit, though is surprisingly scarce.
If diet drinks substantially improved obesity of diabetes, then we would expect that as we increased use of diet drinks, obesity and diabetes would either stabilize or decrease.
From 1960-2000 there has been a 400% increase in the use of diet drinks. The second most popular drink in the world after Coca Cola is Diet Coke, after all. However, the obesity and diabetes epidemic has continued unabated. The only logical conclusion is that diet drinks don’t really help.
Actually, there is substantial evidence that diet drinks may be quite harmful. Dr. Fowler in “Fueling the Obesity Epidemic?” studied 5,158 adults in the San Antonio Heart Study. The risk of becoming overweight in the 7-8 years of follow up was increased by 47% by the use of artificially sweetened drinks. As Dr. Fowler writes
These findings raise the question whether AS (artificial sweetener) use might be fueling—rather than fighting—our escalating obesity epidemic.
Rather than reducing risk of cardiovascular disease, diet sodas may actually increase the risk. But why? Reducing sugar intake should be a laudable goal. Since sweeteners contain no calories or sugar, this should be beneficial. Sweeteners also do not seem to raise insulin levels.
Let me put it this way. Reducing dietary sugars is certainly good. But it doesn’t mean that replacing sugar with completely artificial, manmade chemicals of dubious safety is a good idea. I mean, pesticides and herbicides are also considered safe for human consumption. That doesn’t mean we should be going out of our way to eat more of them. (Anti-organic foods? Extra pesticides for worm free apples!).
There are simply too many things that can go wrong with the ingestion of chemicals such as aspartame, sucralose, or acesulfam-K. These are not foods. There is nothing food like about them. They are synthesized in a chemical vat and sold to you because they happen to be sweet and not kill you in the amounts used in foods. Glue won’t kill you either. That doesn’t mean we should be eating it.
Imagine if they advertised “Glue – tastes good and it won’t kill you, so you should eat more!” (at least one kid in every classroom seems to love the glue stick a little too much). Imagine if they advertised “Aspartame – tastes good and it won’t kill you, so you should eat more!”
The bottom line is that these chemicals do not help weight loss. They may actually cause weight gain. These artificial chemicals may cause cravings that may induce over-eating of sweet foods. By continually eating sweet foods, even if they have no calories, may lead us to crave other sweet foods that may contain sugar or starches.
At the end of 2 years, it is clear that the diet soda (experimental) group was consuming less sugar than the regular (control) group. That’s good. However, if you look at the weight gain, there is no significant difference between the two groups.
In the very same issue of the New England Journal of Medicine, there was another trial reported “A Trial of Sugar-free or Sugar-Sweetened Beverages and Body Weight in Children“.
A group of 641 normal weight children were randomly assigned to continue drinking as previously, or switched to diet sodas.
In this case, there was a statistically significant difference between the 2 groups. However, the difference in weight gain is not as dramatic as many hoped. The diet soda group weighed about 1 kg (2.2 lbs) less at the end of 18 months.
So, yes, drinking diet soda will reduce sugar intake. But no, it will not help reduce your weight very much. This, of course, you already knew. Consider all the people you see drinking diet sodas. Do you know anybody at all who has said that drinking diet soda made them lose a lot of weight?
Undoubtedly, their sugar intake was reduced. But their weight was not. This is true for everybody. This is common sense, which doesn’t seem so common in academic medicine or nutrition. Weight aside, it is also possible that drinking diet soda may be associated with health problems.
At the March 2014 American College of Cardiology meeting, data was presented that showed an association between drinking diet soda and heart disease. Following 59,614 women over 8.7 years in the Women’s Health Initiative Observational Study, there was a 30% increase risk of cardiovascular events (heart attacks and strokes) in those drinking 2 or more diet drinks daily.
This certainly does not prove that diet drinks cause heart disease. This is an observational study and cannot be used to show causation. You cannot prove that diet sodas are bad for you. However, it is very strong evidence against the presumption that diet drinks are good for you. So why would the ADA and AHA endorse something that is certainly not good for you? I have a guess – it starts with M and rhymes with honey. Also known as filthy lucre.
A large problem with most nutritional research is that there are often conflicting reports. One study will show a benefit and another study will show the exact opposite. Why is this? Generally, the deciding factor is who has paid for the study.
Consider the case of sugar-sweetened beverages (SSB). In this study, researchers looked at 17 different reviews of SSBs and weight gain. 83.3% of studies that were sponsored by food companies did not show a relationship between SSBs and weight gain. But in studies that were independent, 83.3% of studies showed the exact opposite – a strong relationship between SSBs and weight gain.
Because research can be used to support whatever viewpoint you have, it is often important to look further into the funding for the study. The final arbiter, though, is common sense. Diet drinks do not make you lose weight. That is common sense. Believe it.
Am I saying that consuming entirely artificial chemicals of unknown toxicity into our bodies because they happen to be sweet is a really, really bad idea? This question kind of answers itself…..
For many health reasons, losing weight is important. It can improve your blood sugars, blood pressure and metabolic health, lowering your risk of heart disease, stroke and cancer. But it’s not easy. That’s where we can help.