What is worse for your health: regular or diet soda?

Nobody mistakes sugar for health food, but the serious impact it has on our health is just beginning to reveal itself in the research literature. For many people, diet soda is an agreeable alternative to sugar sweetened beverages, but the question arises; is diet soda any better for you than regular soda? A fascinating new study out of Harvard University helps us answer this question.

The Article

In this investigation, 37,716 men from the Health Professional Follow-up Study and 80,647 women from the Nurses’ Health Study were followed for 28 years (Reference 1). Sugar sweetened and artificially sweetened beverages were measured repeatedly throughout the follow-up. The outcomes were risk of cardiovascular death, cancer death and death from any cause. Here are some of the more interesting findings in this important study:

 -When compared to subjects that rarely drank soda, subjects who drank 2 or more sodas a day had a 21% higher risk of mortality, a 31% higher risk of cardiovascular disease and a 16% higher risk of cancer.

 -When compared to subjects that rarely drank diet soda, subjects who drank 2 or more diet sodas a day had a 4% higher risk of mortality and a 13% higher risk of cardiovascular disease. Diet sodas were not associated with risk of cancer.

 -Substituting one diet soda per day for one regular soda per day reduced risk of total mortality by 4%, cardiovascular disease mortality by 5% and cancer mortality by 4%.

Conclusions And Recommendations
This is a very well done study that tells us a lot. The take home messages here are the following:

1) Sugar is really harmful to our health. This study shows us an increased risk of disease and mortality with even moderate consumption. A statistically significant increased risk of mortality was found with just 2-6 servings per week. Sugar is also really addictive. The best advice is just to avoid it completely.  In the context of a blood sugar stabilizing diet, after 2 weeks, you won’t even miss it. I know this last sentence sounds hard to believe, but in my own experience and that of my clients, it is absolutely true.

2) Diet soda was far less harmful to our health. This may be a surprise to a lot of people who believe that artificial sweeteners are more or less a poison. They are actually quite well tested and well-designed research studies (such as this) have shown that they are safe, especially when consumed moderately.

3) A couple of notes when comparing regular soda to diet soda:

 -When comparing extreme quintiles, regular soda had over 5 times the risk of mortality than diet soda.

 -Diet soda was not associated with risk of mortality in those that consumed it moderately, which was less than 2 servings per day.

 -There was no association between diet soda and mortality in men, regardless of how much was consumed. The association was only seen in women.

As far as recommendations, there are 2:

1) Avoid sugar sweetened beverages, they are harmful to our health and are addictive. 

2) An occasional diet soda can be a real treat. Just don’t go overboard. Diet soda can perpetuate cravings for sweet foods and due to the cephalic response, may trick the body into releasing insulin. I generally tell my clients that they can include artificial sweeteners on their cheat meals, which is 2 meals per week. The rest of the time, drink water, decaf coffee/tea and my personal favorite, flavored club soda.

References

1) Malik VS et al, Long term consumption of sugar sweetened and artificially sweetened beverages and risk of mortality in US adults. Circulation 2019; 139:2113-25.