You could try digestive enzymes to see if they help. When I first started gaining with heavy whipping cream, I had a very tough time with nausea and gastrointestinal discomfort.
It turns out I was just drinking too much in one sitting. There's a limit to how much fat the body can absorb per meal, and it takes some time to digest those fats.
Instead of trying digestive enzymes, I just reduced the amount I was drinking. That solved my problems, and I'm still able to gain at a very good rate.
4 years