How do you know you not eating enough.

[Cmstewart 7]

How will I know if Im not eating enough? I was told to eat when stomach growled, This has not happened and I get a weird feeling. I drank a Protein shake for Breakfast, I eat a Protein Bar around 12 noon, then for supper I eat some roasted chicken and have a snack of cheese. Let me know your expenince, I never feel what I used to know as hungry. all is different now.

[msfitn2014 248]

my dr and nut said I should be eating around 600-800 cal a day. I measure my food and I keep up with it on mfp and mfp always tell I have not ate enough. I am full, I have a shake for Breakfast, a snack, lunch and sometimes I eat dinner and sometimes I don't I have a shake. I try to stay on a schedule m-f when Im at work because Im not hungry Im just eating to the schedule so I can get my Vitamins, nutrients and Protein in. On the weekend I don't follow a schedule and sometime I forget to eat because Im not hungry and my cal intake is less than 600 some weekends. I usually burp while eating and feel tired and I know im full and I stop eating