The oncology dietician from Mayo told me to eat 2500 calories and have 120 grams of protein each day during radiation. My wife, and caretaker, used these recipes:

Smoothies

Peanut Butter Banana Smoothie – High Calorie, High Protein

½ cup whole milk OR a nutrition drink
1 frozen banana
¼ cup peanut butter
½ cup whole fat yogurt
¾ scoop protein powder
2 packs Stevia or a tablespoon of honey
2 tbs cream or half-and-half
Salt (just a pinch)

he recipe as it’s written was good early in treatment, but it got too thick for Steve around week 4. You can add water or use more milk or nutrition drink to thin it out. Thinning it out makes more volume, but I ⁶
Instead of milk, I often use a bottle of Core Power Elite, chocolate or vanilla (14 oz). That seems to make the perfect consistency for Steve, even though it ends up being 2 glasses of smoothie.

Sometimes I use Boost Very High Calorie, Vanilla (8 oz) instead of milk.

I add the cream or half-and-half at the end and stir it in by hand. I’m not sure, but it seems that blending it made the cream get too thick.

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Mango Smoothie – high calorie

1 cup frozen mango
1 cup whole milk or a nutrition drink
¼ cup yogurt
1 tbl honey or 1 pkg stevia
1-2 tbs heavy cream or half-and-half
1 scoop protein powder

I add the heavy cream at the end and stir it in by hand. It seems to get too thick if I blend it in the blender.

I often use Boost Very High Calorie Vanilla flavor instead of milk.
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Mixed Berry Smoothie

1 ½ cups Naked Juice (Berry Blast)
1 Frozen banana, sliced
1 ½ cups Mixed frozen berries
¾ cup Greek yogurt (5% fat)
1 tbl Honey

Sometimes I have to add water to thin it out enough.