La Croix contains zero calories, zero sugar, and zero sweeteners, which makes it a far better choice than soda or juice when you’re trying to lose weight. But whether the carbonation itself helps or hurts your efforts is more complicated than the nutrition label suggests.
What’s Actually in La Croix
La Croix is carbonated water with natural flavors. That’s it. Every line on the nutrition panel reads zero: zero calories, zero sweeteners, zero sodium. The “natural flavors” are derived from plant-based sources like fruit essences and oils. There are no artificial sweeteners like aspartame or sucralose, no added sugar, and no synthetic ingredients. From a pure calorie standpoint, drinking La Croix is essentially the same as drinking water.
This is where the weight loss appeal comes in. If you’re currently drinking regular soda (around 140 calories per can), sweet tea, or fruit juice, switching to La Croix eliminates those calories entirely. Replacing two sodas a day with sparkling water cuts roughly 280 calories from your daily intake, which over time adds up to meaningful weight loss without changing anything else about your diet.
Carbonation May Increase Hunger
Here’s the less encouraging part. A study covered by UCLA Health found that carbonated water, even without any sweeteners, causes your body to produce significantly more ghrelin, the hormone that tells your brain you’re hungry. In a small human trial, 20 men who drank carbonated water had triple the blood levels of ghrelin compared to those who drank still water or degassed sparkling water. The researchers concluded that the carbon dioxide itself was driving the increase in ghrelin production.
This finding was consistent across both animal and human portions of the study. Rats drinking carbonated water also showed elevated ghrelin levels. The implication is straightforward: sparkling water might make you feel hungrier than still water would, potentially leading you to eat more. If you notice that you tend to snack more when drinking La Croix throughout the day, this hormonal response could be the reason.
It’s worth noting this was a single study with a small sample size, and the effect may vary from person to person. But it’s the most direct evidence we have on carbonation and appetite, and it cuts against the idea that sparkling water is interchangeable with still water for weight management.
The Fullness Factor Is Real but Brief
On the flip side, carbonation does temporarily expand your stomach. The carbon dioxide gas increases total gastric volume, which can create a short-term sensation of fullness and even mild bloating. Some people use this to their advantage by drinking sparkling water before a meal to eat slightly less.
The catch is that this feeling doesn’t last. Gas dissipates quickly, either through burping or absorption. So while a can of La Croix right before dinner might help you slow down and eat a smaller portion, sipping it throughout the day won’t suppress your appetite in any sustained way. In fact, given the ghrelin findings above, the net effect over a full day could tip toward increased hunger rather than reduced hunger. Women may also experience more discomfort from carbonated beverages, as research shows they tend to retain more fluid in the stomach after drinking them.
La Croix vs. Still Water for Weight Loss
Sparkling water hydrates just as well as still water. Research from Loughborough University measuring the Beverage Hydration Index found that sparkling water scores a 1.0, identical to plain water, though it absorbs slightly more slowly. So you’re not sacrificing hydration by choosing La Croix.
The real question is what La Croix is replacing. If it’s replacing soda, energy drinks, or sweetened coffee, it’s an excellent swap that removes empty calories from your diet. If it’s replacing plain water, the trade-off is less clear. You gain a more enjoyable drinking experience that might help you stay hydrated, but you also introduce the possibility of increased ghrelin production and temporary bloating. For most people trying to lose weight, the flavor and fizz of La Croix makes it easier to avoid calorie-dense drinks, and that practical benefit likely outweighs any modest hormonal effect from the carbonation.
How to Use La Croix in a Weight Loss Plan
The most effective way to use La Croix for weight loss is as a direct replacement for caloric beverages. Every sugary drink you swap out is a net calorie reduction with zero willpower required beyond the switch itself. Many people also find that the slight sweetness of flavored sparkling water satisfies a craving for something other than plain water, which helps them avoid reaching for juice or soda.
If you’re concerned about the ghrelin effect, a few strategies can help. Drink La Croix with meals rather than on an empty stomach, since ghrelin’s hunger signal is strongest when your stomach is already empty. You can also alternate between sparkling and still water throughout the day rather than relying exclusively on carbonated options. Drinking a can before a meal to take advantage of the temporary fullness effect, then switching to still water between meals, gives you the best of both approaches.
La Croix isn’t a weight loss product, and no beverage is. But as a zero-calorie, zero-sweetener alternative to the drinks that contribute most to excess calorie intake, it’s one of the simplest swaps you can make. Just be aware that the bubbles themselves aren’t neutral, and pay attention to whether your appetite shifts on days you drink more of it.