trichic:
People worry way too much about the food they eat. Athletes can be very obsessive about it. Eat "normally." That means at least 3 meals a day or maybe more smaller meals. It's easier for the body and easier on the body to process smaller amounts of food rather than fewer large meals. Large meals also require lots of insulin secretion (spikes) which is not very good for the body either.
Don't skip meals if you are training hard. As a female, society places a lot of pressure on you to weigh 125 lbs or less. Many women feel fat if they weight more than 125 pounds or so, regardless of height. If you are a supermodel living on heroin, coffee, and cigarettes, you can get away with it, but as an athlete you need to eat. This may mean going well over 125 lbs.
Many succesful athletic women in many varieties of sports weigh much more than this. Although women don't experience the muscular hypertrophy (growth) that men do, they still pack on weight in the form of muscle and will hold more glycogen (stored carbs) and water, not only the tisses, but from increased blood plasma as well. All of this will add weight to your frame. Many top male and female riders over the years have commented on performance declines when bodyfat stores got too low.
Extreme low bodyfat can also lower your overall health and immunity. The body needs fat to survive and you would die without it. Your body gets worried if its fat stores get too low, thinking if the trend continues, it will die. Even very lean people have more than enough fat for day-to-day life, but there seems to be genetic threshold that is highly variable among individuals which the body tries to maintain. Go below this level and the body may not work as well.
Healthy bodyfat levels for most male riders is around 8-10%, and around 15% or so for females. You may climb faster at a lower bodyfat percentage, but it may effect your health. This is an individual thing and you will have to see over time what works for you.
As for being a vegetarian and an athlete, you must have a decent nutritional backgound on how to combine the proper non-animal food sources for the proper compliment of essential amino acids. This can be a real problem if you are travelling late at night somewhere, and the only thing open is a burger joint.
Protein synthesis (growth) ceases completely when the essential amino acids are not present. All animal souces (milk, meat,egg) have 100% of essential amino acids, where as all vegetables are always "incomplete." You cannot repair muscle tissue, make insulin, estrogen, make new blood cells, grow hair, skin, etc. without the full complement of essential amino acids.
For example if you only ate beans or only ate rice, you would be lacking in the full compliment of amino acids at any given meal. Combine beans and rice with the same meal, and you will have the full compliment of esential amino acids, and growth will take place. Restrict the essential amino acids and growth and repair cease. So, be sure you know how to combine food properly. Since you are in school, why not take a nutrition course for some of your elective credits?.
B vitamin deficiencies, and especially vitamin B12 deficiencies are common for vegans (no animal products), since dietary B12 can only be found in meat, milk, or eggs. So if you are a vegan, take some supplements with the full compliment of B vitamins to ward off any problems. Most vitamins in pill form are poorly absorbed. You will absorb more of your pill-based supplements if you turn them into a powder in a food processer and mix the powder into a fruit drink or "smoothie."
If you would allow yourself to consume milk, cheese, or eggs with your meals, you don't have anything to worry about.
If you are serious about weight, get your bodyfat tested. If you are at 25% you have some fat to loose but if you are at a healthy 15% just accept what the scale tells you. As a female you might be able to get down to 10% or so with strict dieting, but it would not be nearly as healthy for your body overall even if you went faster on the bike.
Low bodyfat levels in women can also cause amenorrhea (cessation of menstruation). Dietary-induced amenorrhea is natures way of telling you your body is not healthy enough to support fetal growth.
As for "healthy" nutrition (whatever that means) people worry too much about processed this or that, etc. True, processed, preserved, or cooked food may lack nutrients compared with unprocessed, natual, uncooked foods. Whole-grain flour versus processed flour is a good example. Just eat a wide variey of food. Don't stress over it. There are only 6 nutients the body needs or can use and they are proteins, fats, carbohydrates, vitamins, minerals, and water. Don't make it more complicated than it needs to be.
I have an extensive weight-training background. I always laughed at guys in the gym who wasted time and money on amino-acid supplements and protein powders. You get the same thing (only cheaper) by drinking a glass of milk.
I knew guys that would literally spend thousands of dollars a year on supplements and only put on 5 pounds of muscle per year in state-of-the-art gyms with the latest equipment and stacks of journals and studies telling them how to train.
Here in the greater Los Angeles area, we have lots of thugs and violent criminals. It's not uncommon to see gang tattoos on people either as customers or employees at the local grocery or hardware store where I live. Many have done prison time. California prisons have restricted access to or made it difficult for inmates to lift weights in prison gyms.
As a result, they just work out in their cells instead of hitting the gym. Wide-grip pullups off the bars and pushups with your cellmate on your back are the primary exercises. On a prison diet consisting of balogna sandwiches, corndogs, and no supplements, it is not uncommon for these prisoners to pack on 20-40 lbs of pure muscle a year!!! Most "experts" who are personal trainers would be lucky to put on half that amount!!!
Yesterday I heard on the radio that the oldest person in America had just died. It was a woman who was 113 years old, and she lived most of her life on "unhealthy" fast food. She lived independently by herself until she was over 100 years old, and out lived her two adult sons. Her favorite foods were Kentucky Fried Chicken and Hostess Twinkies!!! Nearly all health "experts" would tell you that diet is about as unhealthy as it gets, yet here we have emperical evidence that shows this is not always true!!! Don't buy into the hype!!!
When your body craves food it it trying to tell you something - EAT!!!
Good Luck!!!