Is powerade good for you

my fiance's mom was fat when we saw her for Christmas , and we saw her maybe a month and a half after christmas she stopped at my house and she was skinny..i mean like really skinny i could not believe it. she said its her "powerade diet" she says she drinks a minimum of 5 powerades per day and that she lost the weight that way with no exercise even. she didnt say anything about food to me but i know she eats takout alot so its definetly not healthy, her son said he thinks shes drinking gatorade all day and night and having a meal for lunch and dinner with no snacking. i want to try this to see if it works but im very overweight and am sensitive to sodium and there is alot of sodium in powerade and gatorade