Doesn't sound right to me. I drink the special K shakes, and I'm good for a couple of hours. I mean it does depend on how many calories your body burns at rest and if you're getting any exercise. It also depends on the brand of shakes. The COSTCO brand is delicious! But wow, a lot of calories. It also depends on keeping busy. At work, I'll drink a shake, and I'm good for a few hours. The colder the better. Making your own protein drinks isn't my way, but Unjury brand powder tastes great, and with non fat yogurt and ice keeps the calories down. Hope this helps.