Hunger - Why 1 day we are not hungry and the next starving?

Why one day do I feel hungry even though I hate decent? and the next I cannot finish the littlest meal?

Today was a hungry day for me.  My stomach felt empty no matter how much I ate.  The only reason I can think of is that I splurged and had pancakes for breakfast.  I usually skip breakfast, and I feel less hungry and more energetic throughout the day when I do.  But today I messed up and ate breakfast, and instead of eating something high in protein I had something high in sugar and simple carbs.  And I felt TERRIBLE all day.  I mean terrible.

So, yeah, for me it's eating lots of carbs, especially early in the day, and not enough protein.  I guess it messes with my glucose levels so my body thinks it's hungry?

I'm wondering if something is a trigger for me. Like morning/afternoon coffee... I stopped creamer and sugar in it.

I am feeling the same way today.  Two weeks ago I was struggling eat atleast 1200 calories.  And today all I can think about is FOOD!

What has saved me today are low cal snacks that are nutritionally good.  Like baby carrots, oven roasted deli meat slices and string cheese.  If I didn't have these filling snacks, I'd be really tempted to eat lots of sugary/fattening foods.

One slice of deli meat, depending on the brand, can have 20 to 60 calories which isn't much.  Rolling a slice over Kraft 2% milk cheese only adds 50 calories.  Add some carrot sticks, apple slices or grapes and you have a decent snack. 

My theory as to why we feel hungrier some days has to do with what we ate/weighed a few days ago.  (Plus hormones which are effected by stress, monthly cycles etc., but I won't get into that, but you should do some research, maybe you'll find your answer).  Anyways, after an indulgent weekend (having drinks with friends) I get cravings for sugary foods and my appetite increases.  Also, if I recently lost some weight my body starts screaming at me that I'm starving and to eat, eat, eat.  

So, my advice is to try to have a daily routine (even on weekends which tends to be my downfall) and when you're body starts craving things, just tough it out.  It will pass in a day or two.  As long as you are eating a healthy amount with lots of nutrients, then you shouldn't worry.  But if you find yourself craving things other than doughnuts and fried chicken, like non-edible stuff like chalk or ashes, or if you develop an insatiable thirst, then get it checked out by a doc.