Definitely lighter. I tried ON Serious Mass and I think it was around 800 calories for one shake with milk, and it sat in my stomach like concrete and I didn't get hungry for hours after I had one. I can mix the protein and olive oil and drink that right after a meal and not feel much of a difference. Or if I drink one between meals I'm usually starting to get hungry again within an hour. Much better for me than something so heavy I don't feel like eating.