WELCOME TO HCM , THIS IS DR.SIVAYOGI,
there is neither no evidence nor any doctor advises multi vitamin pills or diet substitutes for lose of weight . its a big bull shit so dont believe ...on some thing that suits for u by blindly following others prescriptions.
Truth is that there is no special medications that decreases your weight gain.
My suggestion :
1. consult a dietician to plan your diet according to your body weight
2. avoid consuming excess of free calories (junks, colas) and fat foods like fried items
3. do aerobic exercises
4. if you want multivitamins naturally eat lot of sprouts and friuts.
5. STOP THINKING OF MEDICATIONS THAT WILL REDUCE YOUR WEIGHT.
hope this will help u