I want to tell you about one of the scariest stretches of my life, because I think a lot of people are living through some version of it right now without connecting the dots.
I was using aspartame like it was going out of style. Diet drinks, sweetener packets in my coffee, sugar-free everything. I thought I was making the responsible choice. No sugar, no calories, no problem. That's what we've all been told.
I thought I was losing my mind
Slowly, I started doing things that frightened me. Not the normal "where did I put my keys" kind of forgetting. Very absent-minded, disturbing things.
I walked away from an open cash register. I left my car running for a long time and completely forgot to turn it off. I felt spacey and foggy-headed, like there was a layer of cotton between me and the world. I honestly thought I was going senile. On top of that, I started getting headaches.
I was alarmed. When your own mind stops being reliable, it shakes you to your core.
The part nobody warns you about: they're addictive
Here's the other thing I noticed. I couldn't stop. The more artificial sweetener I used, the more I wanted. It was so easy to overdo, because it was "free." There was no sugar and no calories to stop me, so there was no limit at all.
That intense sweetness never let my taste buds settle down. Instead of my cravings fading over time, they stayed switched on, all day long. For someone trying to keep weight off, that's the exact opposite of what you want.
Then I stopped
When I finally cut out aspartame, all of it went away. The fog lifted. The forgetfulness stopped. The headaches stopped. I felt like myself again.
I'm not a doctor, and I can only tell you what happened to me. But I'm far from the only one. Over the years, I've heard other people describe exactly the same thing: the spaciness, the foggy head, the headaches. Once I started listening for it, I heard it everywhere.
What the research says
I wanted to know whether this was just me, so I looked into it. The honest answer is that the science is still mixed, and people seem to react very differently. But there's enough there to take seriously:
- Headaches are one of the most common complaints people have reported to the FDA about aspartame. Some controlled studies found people who considered themselves sensitive did get more headaches on aspartame, while others found no difference.
- Mood and thinking. In one small study, healthy adults who ate a high-aspartame diet for just over a week reported more irritability and depression, and did worse on a test of spatial orientation, compared with a low-aspartame diet.
- The World Health Organization advised in 2023 that non-sugar sweeteners shouldn't be relied on for weight control, and that same year its cancer research agency classified aspartame as "possibly carcinogenic to humans," while noting the evidence is limited.
None of that proves aspartame caused what I went through. But it does tell me I wasn't imagining it, and that "no sugar, no calories" doesn't mean "no effect."
For a deeper look at the research on diet drinks, read Soda: The Full Story, Regular and Diet.
What I use now
I didn't give up sweet things. I just switched to plant-based sweeteners that don't do any of this to me. My coffee is still sweet every morning, and I still have a fizzy drink when I want one.
If you want to make the switch, these are the sweeteners that don't cause problems for me, and that barely touch your blood sugar:
- Monk fruit, a plant-based sweetener with zero calories
- Stevia, also plant-based and zero calories (try a few brands, since some have a slight aftertaste)
- Allulose, a rare sugar that tastes and bakes a lot like the real thing
Check the ingredient list before you buy. Some "monk fruit" and "stevia" products are mostly fillers that do raise your blood sugar.
My go-to sweetener
This is what goes in my coffee every single day. No sugar, no calories, steady blood sugar, and it's absolutely delicious.
Zevia
My favorite for when I miss soda. The fizz and flavor of the real thing, sweetened with stevia instead of artificial sweeteners, with zero sugar and zero calories.
You can also find sweeteners like these, and Zevia, at MOM's Organic Market, one of my favorite places to shop. They're not meant to be the center of your diet, but as a replacement for a bad habit, they're a game changer.
If any of this sounds familiar
If you're using a lot of artificial sweeteners and you've been feeling foggy, forgetful, or getting headaches you can't explain, it might be worth an experiment. Cut them out completely for a few weeks and pay attention to how you feel.
For me, the answer was sitting in my coffee cup the whole time. Once I quit, every one of those symptoms went away. If yours don't clear up after you cut them out, that's your sign to check in with your doctor, because memory problems and headaches can have other causes too.
This article reflects my personal experience and is not medical advice. Some links on this site go to products I personally use. If you buy through them, I may earn a small commission at no extra cost to you. As an Amazon Associate I earn from qualifying purchases.