nothingbetter
I don't now if pepsi max could slow or stop weight loss. It has some calories and carbs, but you're talking about being on what amounts to a 20 or 30 calorie a day diet if drinking like a liter a day - I have no idea if thats enough to effect weightloss but it might be because it might be enough to keep one on the edge of ketosis and glucose based metabolism - which I would speculate might actually speed up weight loss because you'd be burning muscle and muscle is heavier per calorie than fat. Of course thats not a good way to increase weight loss since it would lead to long term difficulty with weight control - not to mention a less desirable health profile and appearance.
However, I bet drinking pepsi max would make a near-fast much much harder to maintain psychologically since one would be continuing to stimulate their taste buds and therefore food cravings. People on diet soft drinks typically don't lose weight compared to
Sugar soda drinkers because they end up eating more food to compensate because the artificial sweeteners stimulate carb cravings.