I drink diet drinks. Sometimes a little. Sometimes a bunch. There is no doubt going straight water is best. If you must drink them try to limit it to once a week or just on 12 oz serving per day or something.
They can stall you. And for me they give me some cravings. My best (oh is it time to eat again - i'm not even hungry) days come when drinking only water.
Also keep in mind that you are limited as to how much sweetener you can have in a day. A typical 355 ml can of diet soda has 125 mg of Aspartame which is 1 1/4 of a serving so just 2 cans would put you at 2.5 out of your daily limit of 3 sweetener servings. If you tend to use sweetener on anything else during the day you can easily go over. Aspartame in and of itself is a big weight loss staller let alone going over the sweetener limit with it.
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