Q&A: What are your thoughts on regular vs. diet soda?
I got this question on Instagram recently, and get it pretty consistently from clients so thought I would answer it here. The regular vs. diet soda (or I guess, “zero sugar” soda) debate has been around for decades, and while opinions are a plenty, science can also help us figure this out for good.
Some background
The most common source of added sugars in the diet are sugar sweetened beverages - regular soda, juice and sports drinks - and these are drinks I do tend to recommend limiting in generally healthy individuals who are not endurance athletes. The caveat here is that if you’re an endurance athlete, sports drinks are an important part of training and racing and provide the body with very necessary quick energy and electrolytes.
Very important notes regarding research
First and foremost, it’s important to point out that in the research linking sugar sweetened beverages to health concerns, correlation does not equal causation. Sugar-sweetened beverages do not cause certain diseases and conditions, but high consumption has been shown to increase risk for them. See the difference? It’s also important to keep in mind limitations in nutrition-related studies, such as confounding lifestyle and dietary factors, and data collection methodology like 24 hour diet recalls, which are often unreliable.
Sugar-sweetened beverages and chronic disease
Ok, now that we’ve got the above in mind… A recent study found drinking two or more sugar-sweetened beverages per day was associated with an increased risk of hypertension, type 2 diabetes, coronary heart disease and stroke. Replacing one serving of sugar-sweetened beverage with an artificially sweetened beverage (e.g., diet soda) was associated with a significantly reduced mortality risk. Another recent study found a higher consumption of juice and soda associated with an increased risk of overall cancer and breast cancer, which may be due in part to an increase in certain fat stores that may promote tumor cell growth. No association was found with artificially sweetened beverages.
Artificially sweetened beverages
Two things first: all artificial sweeteners currently in sugar sweetened beverages are generally recognized as safe (GRAS) by the FDA, meaning they have been shown to be safe for its intended use. Second, research on artificially sweetened beverages and disease risk is mixed, and much of it has been conducted on animals. For example, in animal studies, saccharin and sucralose have been found to negatively impact gut bacteria, but long-term human studies are necessary to determine if that impact is similar, and how this may affect health over time. Other studies find no association with artificially sweetened beverages and diabetes risk, and another study found women drinking two or more artificially sweetened beverages per day may have a higher incidence of stroke and heart disease. A comprehensive review on aspartame found no credible evidence that it, even when consumed in higher doses, it’s cancer-causing.
Does diet soda increase sugar cravings?
There is plenty of anecdotal evidence linking artificially sweetened beverages to an increase in cravings for sweets and an increase in overall energy intake. One hypothesis here is that because artificial sweeteners do not contain calories, they may confuse the brain and increase the urge to eat more in order to match calorie consumption to perceived sweetness. The study referenced above also concluded that aspartame doesn’t increase hunger in those who consumed it. An interesting study on fruit flies found that artificial sweeteners may affect the area in the brain that senses sweetness of foods and its energy (calorie) content. We are, of course, not fruit flies so more research is certainly needed.
Ok, so what do I think?
Well, as always we can’t look at these things in a vacuum. Dietary patterns as a whole over time are the most important for health, not any one food or even beverage like these. However, either diet or regular soda is fine in small amounts as most of the research links health risk to drinking large quantities of these beverages on a regular basis. My recommendation: if you find yourself having two or more diet or regular sodas per day, try scaling back and choosing other options like sparkling or regular water, or unsweetened iced tea.
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