I drink Protein shakes as a meal replacement in the morning...the one i usually drink is a soy protein shake that is 170 a scoop per 8 ounces. I brought a shaker bottle when i was doing my pre op diet so i just use that to measure. I take 8 ounces of fat free milk, which i would check the calories on the mill i try to buy milk that is 90 calories and the only place i can find it is stop and shop but just look around.
Honestly, i switch it up one week ill drink shakes for breakfast and one week ill eat a 1/2 a cup of food just your preference. What i have noticed is having six small meals instead of three has helped alot. I eat alot of fruit and yogurt as well.
I also tried to keep track of all the foods i eat and calories that are in them. Im also considering becoming a vegan or a Pescetarian because i have a hard time with alot of meats and plus i would miss chicken, red meat, or pork.
Hopes this help