Many people find this hard to do in real life, hence the use of meal replacement shakes in order to remove this variable. (optimisingnutrition.com)
Many popular weight loss diets and protocols are proponents of protein shakes as meal replacements and preach the benefits of high protein diets. (mindbodygreen.com)
I do not recommend protein powder do be used for meal replacements for more than two meals. (hardgainermusclebuilding.com)