Where Does The Fat Come From? - Story of the Fat Cell Part 2

Insulin
When you eat a candy bar or a meal, the presence of glucose, amino acids or fatty acids in the intestine stimulates the pancreas to secrete a hormone called insulin. Insulin acts on many cells in your body, especially those in the liver, muscle and fat tissue. Insulin tells the cells to do the following:

• Absorb glucose, fatty acids and amino acids
• Stop breaking down:
  • glucose, fatty acids and amino acids
  • glycogen into glucose
  • fats into fatty acids and glycerol
  • proteins into amino acids
• Start building:
  • glycogen from glucose
  • fats (triglycerides) from glycerol and fatty acids
  • proteins from amino acids

The fatty acids are then absorbed from the blood into fat cells, muscle cells and liver cells. In these cells, under stimulation by insulin, fatty acids are made into fat molecules and stored as fat droplets.
It is also possible for fat cells to take up glucose and amino acids, which have been absorbed into the bloodstream after a meal, and convert those into fat molecules. The conversion of carbohydrates or protein into fat is 10 times less efficient than simply storing fat in a fat cell, but the body can do it. If you have 100 extra calories in fat (about 11 grams) floating in your bloodstream, fat cells can store it using only 2.5 calories of energy. On the other hand, if you have 100 extra calories in glucose (about 25 grams) floating in your bloodstream, it takes 23 calories of energy to convert the glucose into fat and then store it. Given a choice, a fat cell will grab the fat and store it rather than the carbohydrates because fat is so much easier to store.

When you are not eating, your body is not absorbing food. If your body is not absorbing food, there is little insulin in the blood. However, your body is always using energy; and if you're not absorbing food, this energy must come from internal stores of complex carbohydrates, fats and proteins.


When you are not eating, or you are exercising, your body must draw on its internal energy stores. Your body's prime source of energy is glucose. In fact, some cells in your body, such as brain cells, can get energy only from glucose.
The first line of defense in maintaining energy is to break down carbohydrates, or glycogen, into simple glucose (sugar) molecules. Next, your body breaks down fats into glycerol and fatty acids where the fatty acids can then be broken down directly to get energy, or can be used to make glucose.

Losing Weight and Losing Fat
Your weight is determined by the rate at which you store energy from the food that you eat, and the rate at which you use that energy. Remember that as your body breaks down fat, the number of fat cells remains the same; each fat cell simply gets smaller.
Most experts agree that the way to maintain a healthy weight is:

• Eat a balanced diet - appropriate amounts of carbohydrates, fat and protein
• Do not eat excessively - for most people, a diet of 1,500 to 2,000 calories a day is sufficient to maintain a healthy weight
• Exercise regularly

Posted in: Weight Loss