Not to make this tougher, but is the amount of calories you want to feed what the calorie count would be for Bo's ideal weight? If so, you might want to gradually reduce the calorie count as Bo loses weight. For example, look at the difference between the calories of what you currently feed vs. what you would feed at Jake's ideal weight. Initially, give him 3/4 of that amount so he gets used to a slightly reduced amount of calories. After a month or two, reduce it by another 25%, and so on. It's kind of like the approach that Weight Watchers uses. As you lose weight, you are allowed fewer "points" rather than taking a drastic reduction that would leave you (or Jake) starving.
Just my 2 cents...