About 46% of men in England and 32% of women are overweight (a body mass index of 25-30 kg/m2), and an additional 17% of men and 21% of women are obese (a body mass index of more than 30 kg/m2 ).
What is Fat?
Most of your body fat is stored as subcutaneous body fat (under the skin). Fat or adipose tissue is found in two places on the human body. There's also some on top of each of your kidneys. Other areas of fat build up in your body depend upon whether you are a man or woman. Men tend to carry fat around the abdomen, chest and behind, whereas women are more prone to fat in their hips, breasts and waist as well as the behind.
Your body contains two types of fat tissue brown fat and white fat. White fat is important in energy metabolism, keeps you warm and cushions the body. Brown fat is found mostly in newborn babies, between the shoulders and is important for insulation.
How Does Your Body Get Fat?
Your body obtains fat from foods, mostly triglycerides. Once the food reaches your intestines large fat droplets get mixed with bile salts from the gall bladder. During this process of emulsification, the fat is broken down into smaller droplets. The pancreas then secretes enzymes which breaks the fat down into fatty acids and glycerol. These get absorbed through the intestinal lining. In the intestinal cell the chemicals are reassembles into triglycerides, this time with a protein coating, which makes them water soluble. They are then released into the lymphatic system and eventually into the blood stream.
How Body Fat is Stored
Fat is stored all over the body in fat cells called adipocytes. A person has developed their total number of fat cells often by late adolescence, form then on your fat cells just expand or shrink to accommodate the fat inside your body. You also have no control over which cells decide to release their fat for energy during exercise. In other words, performing leg lifts will not stimulate fat to be released from the fat cells in the legs. Performing abdominal crunches will not help you lose fat in and around just your stomach. Fat from all over the body will be used to fuel your exercise.
How is Weight Gained?
For most people putting on weight is a slow process. If you eat just one slice of bread more than you body actually needs in one day, you are eating about 75 unneeded calories, which would be stored as fat. If you eat this much extra every day for a year you would have eaten about 27000 calories extra that makes 270,000 extra calories in 10 years. Those 270,000 extra calories would add up to approximately 20 Kg (3 stone) of excess weight.