Which of these has the least carbohydrates?
This roll of bread?
This bowl of rice?
Or this can of soda?
It's a trick question.
Although they may differ in fats, vitamins, and other nutritional content, when it comes to carbs, they're pretty much the same.
So what exactly does that mean for your diet?
First of all, carbohydrate is the nutritional category for sugars and molecules that your body breaks down to make sugars.
Carbohydrates can be simple or complex depending on their structure.
This is a simple sugar, or monosaccharide.
Glucose, fructose, and galactose are all simple sugars.
Link two of them together, and you've got a disaccharide, lactose, maltose, or sucrose.
Complex carbohydrates, on the other hand, have three or more simple sugars strung together.
Complex carbohydrates with three to ten linked sugars are oligosaccharides.
Those with more than ten are polysaccharides.
During digestion, your body breaks down those complex carbohydrates into their monosaccharide building blocks, which your cells can use for energy.
So when you eat any carbohydrate-rich food, the sugar level in your blood, normally about a teaspoon, goes up.
But your digestive tract doesn't respond to all carbohydrates the same.
Consider starch and fiber, both polysaccharides, both derived from plants, both composed of hundreds to thousands of monosaccharides joined together, but they're joined together differently, and that changes the effect they have on your body.
In starches, which plants mostly store for energy in roots and seeds, glucose molecules are joined together by alpha linkages, most of which can be easily cleaved by enzymes in your digestive tract.
But in fiber, the bonds between monosaccharide molecules are beta bonds, which your body can't break down.
Fiber can also trap some starches, preventing them from being cleaved, resulting in something called resistant starch.
So foods high in starch, like crackers and white bread, are digested easily, quickly releasing a whole bunch of glucose into your blood, exactly what would happen if you drank something high in glucose, like soda.
These foods have a high glycemic index, the amount that a particular food raises the sugar level in your blood.
Soda and white bread have a similar glycemic index because they have a similar effect on your blood sugar.
But when you eat foods high in fiber, like vegetables, fruits, and whole grains, those indigestible beta bonds slow the release of glucose into the blood.
Those foods have a lower glycemic index, and foods like eggs, cheese, and meats have the lowest glycemic index.
When sugar moves from the digestive tract to the blood stream, your body kicks into action to transfer it into your tissues where it can be processed and used for energy.
Insulin, a hormone synthesized in the pancreas, is one of the body's main tools for sugar management.
When you eat and your blood sugar rises, insulin is secreted into the blood.
It prompts your muscle and fat cells to let glucose in and jump starts the conversion of sugar to energy.
The degree to which a unit of insulin lowers the blood sugar helps us understand something called insulin sensitivity.
The more a given unit of insulin lowers blood sugar, the more sensitive you are to insulin.
If insulin sensitivity goes down, that's known as insulin resistance.
The pancreas still sends out insulin, but cells, especially muscle cells, are less and less responsive to it, so blood sugar fails to decrease, and blood insulin continues to rise.
Chronically consuming a lot of carbohydrates may lead to insulin resistance, and many scientists believe that insulin resistance leads to a serious condition called metabolic syndrome.
That involves a constellation of symptoms, including high blood sugar, increased waist circumference, and high blood pressure.
It increases the risk of developing conditions, like cardiovascular disease and type II diabetes.
And its prevalence is rapidly increasing all over the world.
As much as 32% of the population in the U.S. has metabolic syndrome.
So let's get back to your diet.
Whether your food tastes sweet or not, sugar is sugar, and too many carbs can be a problem.
So maybe you'll want to take a pass on that pasta sushi roll pita burrito donut burger sandwich.
Ever since I was a young girl, I was always fascinated -- (Laughter) Oh!
(Laughter) OK, I meant younger and more short.
(Laughter) If that's possible to imagine.
But ever since I was a young girl, I was always fascinated with how the world worked exactly how it did.
So this, very early on, led me to the fields of mathematics and chemistry.
I would keep going further and further, and as I kept going, I realized that all the fields of science are interconnected.
And without one, the others have little or no value.
So, inspired by Marie Curie and my local science museum, I decided to start asking these questions myself and engage in my own independent research, whether it be out of my garage or my bedroom.
I started reading journal papers, started doing science competitions, started participating in science fairs, doing anything I could to get the knowledge that I so desperately wanted.
So while I was studying anatomy for a competition, I came across the topic of something called chronic wounds.
And one thing that stood out to me was a statistic that said that the number of people in the United States with chronic wounds exceeds the number of people with breast cancer, colon cancer, lung cancer and leukemia, combined.
Hold up.
So what is a chronic wound?
(Laughter) And why haven't I heard about a 5K walk for chronic wounds, why haven't I even heard about a chronic wound in general?
(Laughter) So after I got past those preliminary questions, and one that I will clarify for you, a chronic wound is essentially when someone gets a normal wound, except it fails to heal normally because the patient has some kind of preexisting condition, which in most cases is diabetes.
So more staggering statistics were to be found as I kept going on in this research.
In the year 2010 alone, 50 billion dollars were spent worldwide to treat chronic wounds.
In addition, it's estimated that about two percent of the population will get a chronic wound at some point in their lifetime.
This was absurd.
So as I started doing more research, I found that there was a correlation between the moisture level inside a wound dressing and the stage of healing that the chronic wound would be at.
So I decided, why don't I design something to measure the moisture level within the wound so this can help doctors and patients treat their wounds better.
And essentially, expedite the healing process.
So that's exactly what I set out to do.
Being a 14-year-old working out of her garage-turned-lab, I had a lot of constraints.
Most being that I wasn't given a grant, I wasn't given a lot of money, and I wasn't given a lot of resources.
In addition, I had a lot of criteria, as well.
Since this product would be readily interacting with the body, it had to be biocompatible, it also had to be low-cost, as I was designing it and paying for it myself.
It also had to be mass-manufacturable, because I wanted it to be made anywhere, for anyone.
Thus, I drafted up a schematic.
What you see on the left hand-side is the early schematics in my design, showing both a bird's-eye view and also one stacking variant.
A stacking variant means that the entire product is consisted of different individual parts that have to work in unison.
And what's shown there is one possible arrangement.
So what exactly is this?
So I had gone on to testing my sensors and as all scientists have stumbles along their work, I also had a couple of problems in my first generation of sensors.
First of all, I couldn't figure out how to get a nanoparticle ink into a printcheck cartridge without spilling it all over my carpet.
That was problem number one.
Problem number two was, I couldn't exactly control the sensitivity of my sensors.
I couldn't scale them up or down, I couldn't really do anything of that sort.
So I wanted something to solve it.
Problem one was easily solved by some scouting on eBay and Amazon for syringes that I could use.
Problem two, however, required a lot more thought.
So this is where this factors in.
So what a space-filling curve does is it aims to take up all the area it can within one unit square.
And by writing a computer program, you can have different iterations of the different curve, which increasingly get close to one unit square, but never quite reaches there.
So now I could control the thickness, the size, I could do whatever I want with it, and I could predict my results.
So I started constructing my sensors and testing them more rigorously, using money that I had gotten from previous science fair awards.
Lastly, I had to connect this data in order to be read.
So I interfaced it with a Bluetooth chip, which you can see here by the app screenshots on the right.
And what this does is that anyone can monitor the progress of their wound, and it can be transmitted over a wireless connection to the doctor, the patient or whoever needs it.
[Continued Testing and Refinement] So in conclusion, my design was successful -- however, science never ends.
There's always something to be done, something to be refined.
So that's what I'm currently in the process of doing.
However, what I learned was what's more important than the actual thing I designed is an attitude that I had taken on while doing this.
And that attitude was, even though I'm a 14-year-old working in her garage on something that she doesn't completely understand, I could still make a difference and contribute to the field.
And that's what inspired me to keep going, and I hope it inspires many others to also do work like this even though they're not very sure about it.
So I hope that's a message that you all take on today.
Thank you.
(Applause)