English to Chinese Medical Medical (general)

Conversely, if your stomach is full of food before you lift your first weight, too much blood will be drawn to your stomach rather than to your muscles, where you want it. And if you do cardio on a full stomach, it will take much longer for your body to start tapping into its fat stores.
试译：
反过来说，如果你在举重前肚子吃得老饱，大量血液就会流向胃部，而不是流向真正需要血液的肌肉。如果你吃得老饱后去做有氧操，人体开始动用贮藏脂肪所需的时间也就越长（？？）。
后半句如何组织比较通顺？