Aspartame is an artificial sweetener found in diet soda, non-sugar sweetener packets and some foods. If you've given up drinking diet soda, you may wonder if any diet soda withdrawal symptoms you've been having — like headaches or trouble focusing — are actually from giving up aspartame.
The jury is still out on whether you need to worry about aspartame withdrawal, but there may actually be another reason for your symptoms.
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Diet Soda Withdrawal
According to Jennifer Bruning, RDN, LDN, a Chicago-based registered dietitian nutritionist and spokesperson for the Academy of Nutrition and Dietetics, there isn't any conclusive evidence that shows whether aspartame withdrawal exists or not. However, that doesn't mean you'll necessarily feel great when you quit that diet soda habit cold turkey.
If you drink a lot of coffee sweetened with aspartame packets every day, or diet cola, and you stop, you're not just cutting back on aspartame. You're cutting back on caffeine too, Bruning says. And caffeine withdrawal, unlike aspartame withdrawal, has been more conclusively shown to exist, Bruning says.
"It's very possible that someone may think: 'Oh, I'm going through withdrawal from aspartame,' when, in reality, they're going through withdrawal from caffeine — which we know to be a true phenomenon," Bruning says.
A September 2013 review article in the Journal of Caffeine Research lists the American Psychiatric Association's diagnostic criteria for caffeine withdrawal. Symptoms include:
- Fatigue or drowsiness.
- Irritability or depressed mood.
- Trouble concentrating.
- Flu-like symptoms (nausea, vomiting or muscle pain/stiffness).
How to Cut Back or Quit
If you're looking to cut aspartame out of your diet, there may be ways to do it that don't feel so bad. One way is to start by cutting back, and slowly decrease your consumption, rather than quit cold turkey. "If we are making a big change to our diet, for some people it can be helpful to kind of ramp down our intake of that item over a period of time," Bruning says.
Another thing she says can help is to try to find a substitute. For example, if it's diet cola you're into, maybe there's an unsweetened iced tea that you might like to try instead.
Bruning says that changing your daily habits isn't easy. Whether you realize it or not, you may get a lot of comfort from your favorite drink, she says. She suggests that if you want to cut it out of your diet but are having a hard time, sometimes getting help from a registered dietitian or nutritionist can help.
What We Know About Aspartame
So now you know you can quit aspartame if you want to — but do you need to? Ultimately, it's up to you. "There are a lot of mixed emotions out there," Bruning says. "The research really shows that it's unlikely to be harmful to humans in any amount that is physiologically possible to consume."
According to the U.S. Food & Drug Administration (FDA), the acceptable daily intake for aspartame is 50 milligrams per kilogram of body weight per day. Translation: You'd have to drink something like 18 cans of diet cola in a day to get to the point where your aspartame intake would be cause of concern, Bruning says.
What's more, FDA notes that aspartame is one of the most comprehensively studied ingredients you can buy, with more than 100 studies supporting its safety.
For one such analysis, the authors of a January 2019 systematic review in BMJ looked at studies on a broad range of health outcomes comparing people who consumed non-sugar sweeteners, including aspartame, and those who didn't. The review found that non-sugar sweeteners are likely to have a small, beneficial effect on overall blood sugar levels and body mass index.
However, on the whole, the review found most studies had limitations that made it hard to say for sure whether non-sugar sweeteners affect things like kidney, heart and oral health; mood and behavior; or eating habits — either in a positive or negative way. In other words, while aspartame is considered safe in the amounts most people consume it, more research is needed to be sure about some of the long-term effects associated with it.
- Jennifer Bruning, MS, RDN, LDN, registered dietitian nutritionist; spokesperson for the Academy of Nutrition and Dietetics, Chicago
- Journal of Caffeine Research: "Caffeine Use Disorder: A Comprehensive Review and Research Agenda"
- BMJ: “Association Between Intake of Non-Sugar Sweeteners and Health Outcomes: Systematic Review and Meta-Analyses of Randomised and Non-Randomised Controlled Trials and Observational Studies”
- U.S. Food & Drug Administration: “Additional Information About High-Intensity Sweeteners Permitted for Use in Food in the United States”