The narration

My persuasive argument thesis is Eating a lot of sugary foods is worse for children than for adults.

1. What do people already know about my topic?

Every person knows that eating too much sugary foods is bad for all people regardless of age. If people eat too much sugar, they can be addicted to it. Also, if it is too much, it can cause a disease like diabetes or tooth decay. 

2. What research has already been done about my topic?

http://www.bbc.co.uk/science/0/21835302 a study that children tend to crave sugar more than adults

http://www.bbc.co.uk/science/0/21843942 I think it would be a good background information that can explain the current situation

http://www.npr.org/blogs/thesalt/2011/09/26/140753048/kids-sugar-cravings-might-be-biological physiological facts why children crave sugar, contains specialists' opinions.

http://www.medicalnewstoday.com/articles/262978.php How much sugar is hidden in your food, want to describe current situation.

3. What are the implications of my argument (What if I'm right? What if I'm right and people ignore me?

If eating sugary foods is worse for children than adults, there will be an increasing need to educate children of eating sugar. Therefore, by educating that eating sugar in an early age is bad, the children's health will be better, and the healthy children will grow as healthy adults.

My narration

 As I talk about the preference for sweet flavors, I will explain you the background information  why children crave sugary foods more than adults in terms of physiology and evolutionary theory. Moreover, I will suggest the risk of eating sweet foods for children in current situation.

Sugar is a simple carbohydrate that belongs to a class of chemically-related sweet-flavored substances. It comes in many different forms. The three main types of sugar are sucrose, lactose, and fructose. First I will tell you why people find sugar so addictive. Sugar can be a dangerous mood booster. It prompts the body to release serotonin, which makes you feel happy, into the blood stream. The instant happiness and joy we get from sugar is why we crave it when we celebrate ourselves and seek comfort and reward. However, the sugar craving that makes us happy triggers an increase in insulin as the body wants to bring blood glucose levels back to normal. This has the knock-on effect of ‘sugar craving’. This is the physiological explanation of the reason why people become addicted to sugar. Especially for children who are growing, the physiological effect is more intense. According to Sue Coldwell, a researcher atthe University of Washington who has studied kids and sweets, and her colleagues, growing bones actually secrete hormones that can influence metabolism. They said metabolic hormones like leptin and insulin have been shown to act on brain areas that control cravings and appetites. It means that the hormones from growing bones of children make them crave sugary foods. 
To understand my thesis, it is important to know the evolutionary theory of craving sugary foods. Many scientists believe a child’s preference for sweet foods is an evolutionary hangover. As children preferred high-calorie foods in times gone by, they would have had a better chance of survival when food sources were unreliable. It has been proven that sugar is a natural pain reliever in children from the research of Mennella who works at the MonellChemical Senses Center. This theory and research suggests the evolutionary evidence that children enjoy sugary foods far more than adults.

However, children’s preference for sweet foods cannot be an advantage anymore in current situation even though it has helped them survive in the past. Rather, it is very dangerous for children to prefer sugary foods in a modern world. In a modern world, manufacturers often add extra sugar to food because it makes them taste better. Even though the information is mentioned in the food labels, the consumers don’t recognize it as sugar because sugar has various forms of words. Therefore, the consumers are impossible to determine the amount of sugar they are eating. They eat sugar more than they imagine without recognizing the truth about sugar.