It really does depend on a lot of variables... What is your current weight and height? What is your typical one meal? Do you pick on anything or snack on anything during the day? Do you drink anything besides water such as soda or anything with calories??
Have you considered a thyroid workup at the doctor's?
Hypothyroidism can cause a decreased appetite and weight gain.
I have hypothyroidism and while I didn't magically lose the weight after starting medication, I felt better.
How many cals are you eating per day? One meal and a couple drinks may not be enough or depending on the type of drinks and size of the meal, may be too much.
The less you do and the less you eat the less you burn until you are over and under eating at the same time.
Eat a little more, do a lot more.
I was also gaining when I was eating just a little. I started eating more fats and proteins along with getting to the gym a bit more and I noticed a difference in about 10 days. I have more energy too.
How many calories would you typically consume in a day? It sounds like you may be severely restricting based on the information given thus far which can cause the body to hold onto every calorie it gets & subsequently not allow you to lose weight.
i know what you mean but I do believe it is true about eating meals through out the day. when i was in high school I ate more than all my friends, i probably ate close to 4000 calories a day and never went over 90 pounds, im 5 and a half feet tall and i now weight 170 pounds. I eat very seldom (ussually just dinner, which i never finish) I intake roughly 800 calories in a day and thats beverages included. i exercise constantly because i have no car and i am a mom, i always walking across town to get to the store or school or daycare or anywhere else i need to go. i put in at least 4-5 hours a day into exercise and still manage to keep gaining extra weight. I have had my thyroid check out and hormone levels taken and am just fine but because i never feel hungry anymore and have to force myself to even eat part of dinner my body just stores away fat from everytime i do eat. i think that is what ur going thru too. the body does this because it feels it has to hoard nutrients because it is not getting what it needs (like how someone would hoard a few pieces of bacon at breakfast because they think everyone else will eat it all). the only thing tht helps me latly and helped me drop 20 pounds is to buy nuts in bulk and bring a baggy of them with u where ever u go and every couple hours make urself eat a small handful (expecially when u wake up). i found this to be the easiest way to do this because i am very seldom ever hungry and i dont have to force myself to eat large quantities ... i hope this helps :)