Crystal Light does not break a fast for most goals. A serving from the classic pitcher mix has about 5 calories and an On-the-Go packet about 10, with no sugar. It is sweetened with aspartame and acesulfame potassium, which barely affect insulin in most studies.
| Calories | ~5-10 kcal per serving |
|---|---|
| Breaks a weight-loss fast? | No |
| Breaks ketosis? | No |
| Breaks autophagy? | Unlikely |
| Insulin impact | Minimal |
The powder is mostly citric acid, mineral salts and flavor, with a little maltodextrin as a carrier. Mixed into a bottle of water, an On-the-Go packet adds about 10 calories, far below the amount that would raise insulin or interrupt ketosis. The sweeteners do the job that sugar does in regular lemonade.
Studies on aspartame and acesulfame potassium mostly show little or no insulin response, though sweet drinks keep cravings alive for some people. Some flavors add caffeine, about 60 mg per packet, so count them toward your daily total. The Crystal Light Pure range uses real sugar with stevia, about 1 g of sugar per serving, which matters only on a strict fast. People with phenylketonuria must avoid aspartame.
One or two bottles a day during your fast are fine. If you notice it makes you hungrier, swap some for plain or sparkling water.
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