Fluctuating Teen (Boy) BMIs

Hello,

I have recently plugged my height and weight into a BMI calculator suited for teenagers, mostly out of boredom, and have found myself to be rather underweight, in the 9th percentile. I am fifteen years old, male, about 117 lbs and 5'9" tall.

I don't have any eating disorder; however, I do walk quite a bit and I eat healthy. During a lot of the Summer, my general day would go as follows:

Breakfast - A cup of oatmeal (1/2 cup plain oats, 1/2 cup flavored, high fiber for flavor)

After-breakfast Snack - Fiber One Bar or other similar bar

Before Lunch Snack - 1 Apple

Lunch - Ham & Cheese on whole grain bread or a bagel with light cream cheese.

Dinner - whatever my family prepares. Often times, I'll eat some form of meat (chicken or pork most often) or whole grain spaghetti.

After dinner I'll often have a yogurt and then eat varying junk or other food before bed. Sometimes carrots, often pretzels/sesame sticks, sometimes even ice cream.

Anyway, arbitrary daily diet information aside, I obviously want to be at a "healthy" BMI and do not want to be starving my body of the calories it needs to grow. That being said, is it normal for some teens to experience natural dips in their BMI as low as the 17s?

If I need to actively work to gain weight, how should I go about it? Should I look at high-cal but healthy foods like nuts, or can I have a field day and chow down on gallons of ice cream? More specifically, do I still have to worry about cholesterol, saturated fats, etc?

You're a teenage boy. Teenage boys are infamous for their sky-high calorie needs and bottomless stomachs. I'd say you're free to up your calorie intake if you're uncomfortable with being skinny - make sure you eat plenty of protein and good fats sparingly, and it's totally fine to have a field day. If you don't mind being "underweight" and feel good where you are, then you don't need to gain weight, obviously. It'll probably come with age.

Also, exercise.