Are sweeteners OK when you quit sugar? Diet soda, stevia and more
Diet soda looks like the perfect loophole: all the sweetness, none of the sugar. Here's what the evidence says, and why we leave sweeteners out.
The short version: sweeteners have no sugar, but they keep the sweet habit alive, and they don't seem to help with weight in the long run. In 2023, WHO advised against using non-sugar sweeteners for weight control after its review found no long-term benefit for body fat. It's a conditional recommendation, so the evidence isn't final. In Sweet Nothing, sweeteners and diet drinks are out at both goals.
Why sweeteners feel like a loophole
When you decide to quit sugar, diet drinks look like the obvious bridge. Same can, same fizz, same sweet taste, zero sugar on the label. Stevia in your coffee, a "zero" energy drink in the afternoon, a protein bar sweetened with sucralose: none of it technically breaks a no-sugar rule.
And for a lot of people, that's exactly the problem. Quitting sugar isn't only about a number on a label. It's about getting to a place where you don't need everything to taste sweet, and where 3 pm doesn't automatically mean reaching for something.
What WHO said in 2023
In May 2023, the World Health Organization published a guideline on non-sugar sweeteners. Its advice: don't use them to control body weight.
The key points:
- No long-term benefit for body fat. WHO's review of the evidence found that sweeteners don't help reduce body fat in the long run, in adults or children.
- It's a conditional recommendation. That's WHO's way of saying the evidence isn't strong enough to be certain. It's guidance, not a ban.
- It doesn't cover people with diabetes. The guideline was written for people without diabetes. If you have diabetes, talk to your doctor before you change what you eat or drink.
- It covers natural sweeteners too. The advice is about non-sugar sweeteners in general, so stevia counts as well as the artificial ones.
For us, that's enough. If sweeteners don't seem to help with weight long term, and they keep the habit you're trying to break, there's not much left in their favor.
The habit argument
This is the reason we care about most. A habit is a loop: a cue (3 pm, after dinner, a stressful email), a routine (reach for something sweet) and a reward (the sweet taste, the little break).
A can of zero changes what's in the routine, but it keeps the loop running. The cue still triggers the urge. You still reach for something sweet. Your brain still learns that the answer to "tired" or "bored" is a sweet taste. And on a day when the zero version isn't around, the regular one is right there next to it.
When you take sweetness out of the loop, something else happens over time. In one study, after about three months of eating less sugar, people rated sweet foods around 40% sweeter. Fruit can start to feel like dessert. It's hard to get there if your day is still full of intensely sweet drinks, whatever is making them sweet.
Read more about breaking the loop in how to stop sugar cravings.
In Sweet Nothing: both goals, "no sweets & sweet drinks" and "no added sugar", leave out diet and zero drinks and sweeteners. Day 15 of the 30-day program walks you through finding them in your own fridge and swapping one out. See how the app works.
Sweeteners and sugar alcohols to know
You'll find these on ingredient lists, often under their names, sometimes as E numbers in Europe. Here are the common ones:
| Type | Names to look for |
|---|---|
| Artificial sweeteners | Sucralose, aspartame, acesulfame K (acesulfame potassium), saccharin, cyclamate, neotame, advantame |
| Plant-based sweeteners | Stevia (steviol glycosides, rebaudioside A), monk fruit (luo han guo) |
| Sugar alcohols | Erythritol, xylitol, sorbitol, maltitol |
A note on sugar alcohols: WHO's sweetener guideline doesn't cover them. We still skip them in Sweet Nothing, for the same habit reason: they keep food tasting sweet. You'll often find them in "sugar-free" candy, chewing gum, keto treats and protein bars.
And remember the other side: honey, agave, maple syrup and coconut sugar aren't sweeteners in this sense. They're sugar, under friendlier names. Our list of hidden sugar names covers those.
Where sweeteners hide
The obvious places are diet and zero sodas. The less obvious ones are products that market themselves as healthy. Check the ingredient list when you see these words on a pack:
- "Light", "lite" or "diet": yogurts, desserts, drinks and dressings.
- "Zero" or "zero sugar": sodas, energy drinks, flavored waters.
- "No added sugar": no added sugar doesn't mean no sweetener. Many "no added sugar" drinks and yogurts are sweetened with sucralose, aspartame or stevia.
- Protein products: protein bars, shakes, powders and puddings very often contain sweeteners or sugar alcohols.
- "Sugar-free" candy and gum: usually sugar alcohols.
- Flavored waters and sports drinks: "lightly sweetened" can mean sugar, sweetener or both.
In Sweet Nothing: not sure what's in something? Scan the barcode or take a photo of the food or its label. The food scanner tells you if it fits your goal, if you should avoid it, or if it's unsure, and why.
What to drink instead
For most people, sweeteners come in a glass. So the real question is: what do you drink now? Some ideas:
- Water, still or sparkling. Keep a cold bottle in the fridge so it's the easy choice.
- Sparkling water with lemon, lime or cucumber. If you love the fizz, keep the fizz.
- Plain coffee or tea, hot or iced. Iced tea with no sugar is a great soda swap.
- Herbal tea: mint, ginger, rooibos, chamomile. Many taste naturally sweet-ish.
- Water with mint or fruit slices for a little flavor.
The first week can feel flat. Then your taste adjusts, and plain sparkling water starts to taste like something. For more, see day 4 of the 30-day challenge: rethink your drinks.
The honest part: what we don't know
We want to be fair about this. Sweeteners aren't sugar, and a diet soda isn't the same as a regular one. WHO's recommendation is conditional, which means the evidence has real limits, and research is still going on.
Skipping sweeteners is Sweet Nothing's approach, and we think it's the best one for breaking the habit. But if diet soda is the only thing keeping you off regular soda right now, that's still a step. Many people use it as a bridge for a short time, then move to sparkling water. What matters most is that you keep going.
New to all this? Start with our step-by-step plan to quit sugar.
Questions people ask
Can I drink diet soda when I quit sugar?
Technically it has no sugar, but in Sweet Nothing diet and zero drinks are out at both goals. They keep the habit of reaching for something sweet alive, and WHO advised against sweeteners for weight control in 2023.
Is stevia OK on a sugar-free diet?
Stevia is natural and has no sugar, but it is still a non-sugar sweetener and it still keeps food tasting sweet. We skip it, along with monk fruit, for the same habit reason as artificial sweeteners.
Do artificial sweeteners help you lose weight?
Not in the long run, according to WHO. Its 2023 review found no long-term benefit for body fat in adults or children, so it advised against using non-sugar sweeteners to control weight. It is a conditional recommendation, so the evidence isn't final.
What should I drink instead of diet soda?
Water, sparkling water, plain coffee or tea, herbal tea, or water with lemon, lime, cucumber or mint. If you love the fizz, sparkling water with citrus keeps the fizz without the sweetness.
Sources
- WHO: guideline on non-sugar sweeteners (2023)
- Wise et al., American Journal of Clinical Nutrition, 2016 (sweet taste)
- WHO: guideline on sugars intake for adults and children (2015)
This guide is general information, not medical advice. If you have diabetes, have or had an eating disorder, are pregnant or take medication, talk to your doctor before you change how you eat.