CHANCES are, you have never heard of leptin. This hormone is, however, very important in the control of fat storage and energy metabolism.
Leptin is a hormone or chemical messenger produced by fat cells. It acts on the brain, causing us to crave food less and feel less hungry. So when we eat enough to increase the amount of fat stored, the fat cells use leptin as a signal to tell the brain that the body has enough energy stored, so stop eating so much. The brain will also speed up the metabolism as leptin has informed it that there are enough energy stores to allow increased energy expenditure.
The opposite is also true. In times of starvation when the fat stores fall, leptin production gets less. The brain senses the low leptin levels, gets the message that the fat stores are low, and increases hunger and cravings. This serves to replenish the fat stores. The metabolic rate also slows down to preserve what little fat there is stored in the body. So it's like giving you information on your bank account — when you should deposit more or when you can save less and afford to spend more.
This regulation of fat stores and energy use works quite well normally. However, in some obese persons, there is a condition called leptin resistance. The overweight individual has a significant amount of fat stored, which triggers the fat cells to release high doses of leptin. These high levels of leptin would normally signal the brain to eat less and speed up metabolism. In leptin resistance, the brain cannot sense the high levels of leptin. Instead it thinks that there are low leptin levels and the individual continues to crave food and feel hungry. The metabolism may also slow down, leading to further weight gain.
If you are experiencing cravings and feel hungry all the time even though you are overweight, you might have leptin resistance. High leptin levels are associated with high blood pressure, obesity, heart disease as well as insulin resistance which may lead to diabetes.
There is no magic cure for leptin resistance. We can only reverse it with a proper diet and exercise programme. Avoiding leptin resistance in the first place is your best bet at staying healthy. Here are some tips to avoid and treat leptin resistance.
1. Avoid high fructose corn syrup (HFCS)
Good luck with this! HFCS is added to many processed foods from sodas to pickles and even medicine. It has been linked to weight gain, heart attacks, stroke and diabetes. As it is everywhere, you need to wean yourself from processed foods to avoid HFCS.
2. Avoid eating carbohydrates with a high glycaemic index
Carbohydrates that raise your blood sugar rapidly also raise your insulin levels rapidly. This insulin converts the high sugar load into fat for storage. Examples of high glycaemic food include bread, rice, Irish potatoes and table sugar.
3. Do not overeat
Eating when bored, while watching TV and eating beyond the point when you no longer feel hungry are ways in which you are overriding the leptin hunger control mechanism. After a while the brain stops listening to leptin if you choose to ignore its signal to stop eating.
This is very important to keep the stress hormone levels low and to avoid stress eating. Stress has been linked to high levels of leptin and subsequent leptin resistance.
Lack of sleep has also been associated with elevated leptin levels and leptin resistance.
Regular exercise will not only burn excess fat but will help to relieve stress and regulate the body's metabolic rate.
Dr Alfred Dawes is a consultant general, laparoscopic and obesity surgeon at Premier Heart and Surgery Centre, and managing director, Mahogany Health and Fitness. Contact him at firstname.lastname@example.org.