I'm not a fan of the meal replacements on the market myself, so I would recommend getting a VitaMix and preparing nutrition that way based on your fathers specific dietary need.

Caloric intake and macro nutrient breakdown (fats, carbs, proteins)widely varies by height, weight, age, activity level etc, so developing a recipe that your father can intake based on these considerations are very important. In my humble opinion, if I can ever be considered humble, nutrition is half the battle really.

Personally I'm sipping on my "dinner" shake (as I no longer eat solids) that I whipped up in my Vitamix. It contains Whey protein, organic baby spinach, oatmeal, natural peanut butter, coconut water, water, kelp, spirulina, & tumeric. It fits in a glass, is smooth as a milk shake and tastes just fine with me. It also has 683 calories, 24.5grams of fat, 75.5 low GI complex carbs, and 45grams of protein.

Now admittedly it's a bit too high in protein, but I'm in recovery from changing up my workout to get into single digit body fat percentage and I "really" wanted the peanut butter that put me over the top on the shake. Right now I'm rocking about 10% body fat at 178lbs and 5'9" tall, 31" waist, 42" chest, 15.5" neck & arms...not bad for someone who's on a liquid diet or a stage IV survivor.

Now compare that shake to your Ensure:

Nutrition Facts
Serv. Size 1 bottle
(8 fl oz)
Calories 250
Calories from Fat 50

6g Fat,
40g Carbohydrate (22grams of sugar, and 1g Dietary Fiber)
9g Protein

Now when I look at the amount of simple sugars in that "meal" and consider that the average cancer patient has significantly elevated Cortisol levels (Cortisol "counteracts" insulin levels) which significantly reduces the amount of insulin in the system, I think it's basically like feeding corn syrup to a diabetic, and the lack of protein won't give the system the building blocks it needs to recover and rebuild.

Just my thoughts for what they are worth.

Eric