I tend to disagree with geoffgart, as usual, on the fat issue. Eating a low fat diet will reduce the effectiveness of yoru steroids, by elevating shbg levels, thus causing a greater percentage of the synthetic androgens in your bloodstream to be bound, and thus metabolically inactive. People on low-fat diets need higher doses of steroids to get the same anabolic effect. Not only that, but outside of the hormone issue, a high fat intake is required to build new muscle tissue, as well as repair microtrauma's to your muscle cells after training.
Sustanon/deca is an overpriced and overrated cycle by the way. You would have been much better off using test enathate for yoru first one. You could make the same gains, with fewer side effects and less $$$. You do realize you are combining an aromatase substrate (testosterone) with a progestin (deca) right? Progestins, especially nandrolone, tend to increase estragen sensitivity. This shouln't really be a problem at the doses you are using, however it is something to consider when you do increase your doses later.