The leaner you become, the longer it takes to lose fat healthily (the key, as you want to preserve as much muscle and strength as possible while losing fat). If you're at 25% body fat, it's very possible to lose 2-3 pounds of fat per week for the first several weeks. If you're at 10% body fat and are making a run for single digits, however, 2-3 pounds of fat per week would be impossible without dangerous drugs.
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