I like using ThermoDynamix during my contest prep mainly to keep me going through the hard low carb days. Personally I think you are wasting your money using a product like this during the off-season. It would be much easier to add a few minutes of cardio or trim your food bit. If you are getting fat, you are either eating too much, eating the wrong combinations of food, eating the wrong types of food.
A trick I use...
Meals 1-3 - low-fat protein, low to moderate glycemic index carbohydrate
Meals 4-6 - protein, vegetables, and healthy fat (olive oil, nuts, salmon, flax seed oil, ...)
Meal 7 - Protein Shake (no carb), Salad with balsamic vinegar or lemon juice
On 1-2 days a week, go high carb to keep your metabolism humming. This day should be 500-1000 extra calories.
Mon - Normal (plan outlined above)
Tue - Normal
Wed - High Carb (6 carb meals)
Thu - Normal
Fri - Normal
Sat - Normal
Sun - High Carb
When I use this plan, I can put on muscle and stay relatively lean.
My advice to clients is always to ask yourself if you can get the same benefit by tweaking your workouts and nutrition. If you can, save your money.