My viewpoint is a bit different.
A spike in insulin levels will make it more difficult for cells to break down and release fat from fat cells back into your blood stream. This may result in weight loss being more difficult, and a feeling of hunger and/or low energy as your body attempts to equalize blood glucose levels. So it’s not a matter of not storing fat, but allowing fat to be released from fat cells.
The discussion of maltodextrin vs aspartame may be a moot one, as it depends upon the quantity of maltodextrin consumed. If only a very, very small amount of maltodextrin is consumed, the insulin levels may only rise a small amount. Whereas if a large amount of maltodextrin is consumed, the rise in insulin levels may be significant.
Although I don’t know if the amount of maltodextrin in jello causes a significant rise in insulin levels, my comment was a general one insomuch as if there is a choice between 2 similar products, one with maltodextrin and one with aspartame, the one with maltodextrin is more likely to cause a rise in insulin than the one with aspartame. Some of the sugar free jello flavor products use maltodextrin, while others don’t. I choose to buy the ones with aspartame to avoid the potential of insulin to rise that may result from the products containing maltodextrin.
JMO