Anyone who has spent a day fasting from food, or who has even skipped a meal, knows just how much time we save when we're not provisioning and consuming meals. Of course, when it comes to eating efficiency won't be our primary concern. If we were to articulate our basic requirements for food, we'd most likely come up with the following: (1) it should give us the nutrition our bodies need (2) it should support our body transformation objectives (e.g. lose fat or gain muscle) (3) it should taste good (4) it should be convenient. Foods that meet two or three of these requirements quickly turn out to be a mainstay in most diets.
Walk into any gym, ask what are the best exercises to lose arm fat and you'll get a different answer from everybody. Even the so called experts won't agree.