Rick,

Bodybuilding weight gain products typically provide about 500-1000 calories per serving. It's different than just protein power, but looks and tastes about the same. I even see them in regular drug stores now. It's not cheap, but should be cheaper than Ensure.

You might also consider a regimen of digestive enzymes and probiotics (about 30 days), which should help your body utilize the food you are eating better.