As a corrective measure, dieting is, by any standard, an absolute disaster.
Around 90-95 per cent of dieters regain the weight they lose and continue on a yo-yo cycle of dieting. The weight gain wreaks havoc with their hormones, setting up a hormonal imbalance with parallels to Type 2 diabetes.
Evidence now suggests that the solution to obesity isn’t a pill or a diet, but an understanding of how the body works.
Society doesn’t help. Two decades ago, the average model weighed eight per cent less than the average woman. Now, the average model weighs 23 per cent less than today’s average woman, so it is unsurprising that we are addicted to dieting.
The problem is that while models have got thinner, everyday women have become fatter.
New evidence is showing that, far from a failure of willpower, failed dieting often results from a broken fat thermostat.
Two recently discovered hormones, leptin and ghrelin, carefully police current fuel and fuel supply, or stored fat, and constantly signal to the brain when more food is required.
When levels of leptin are high, and levels of ghrelin low, the brain knows you have had enough food, thereby creating a feeling of satiety.
The reverse hormonal situation tells the brain that you need more food and it gets to work, making you feel hungry.
In overweight people this complex signalling system is often scrambled. The brain is deaf to any messages about energy supplies and consequently creates a situation whereby the individual is constantly hungry.
Likewise, when people undergo a crash diet and leptin levels fall, the brain thinks you are starving and stimulates great hunger to restore your leptin levels to normal.
In addition, bad lifestyle habits, such as eating too much sugar, processed food or living under constant stress can cause the brain to stop responding to this hormonal signalling. Another factor in obesity is chronic sleep deprivation.
The complex interrelationship between the two ‘fat’ hormones and the rest of the body, together with what you eat, how well you sleep, exercise and how you cope with stress all suggest that dieting is too narrow a solution for obesity.
Today and next Sunday I will look in more depth at the ‘fat’ hormones and how they can keep you fat.
A few years ago a group of Spanish doctors studied 105 overweight men and women in their 20s and 30s. They were put on an eight-week calorie-restricted diet.
Generally the diet was successful; the average weight loss was five per cent of their body weight. Four months later, the researchers checked the participants to see if their weight had stayed off.
A number had regained their weight. However, it was noted that it wasn’t connected to the food they ate but it had mostly a strong connection to their hormones. The ‘fat’ hormones were malfunctioning; they no longer offered the brain the right information about food.
In this study those who had regained weight had higher levels of leptin and lower levels of ghrelin, which made the researchers conclude that these ‘appetite-related’ hormones may play an important role in weight regain after dieting.
These hormones were discovered in the 1990s, so this is a new look on the way our body works. They are agents that regulate appetite.
Leptin is made in our stored fat cells, or adipose tissue stores, and is a protein hormone that circulates through the bloodstream as a signal to the brain regarding the body’s level of fuel and whether it is providing an adequate amount of energy.
Whenever you finish a meal, leptin is released from the fat stores and enters the bloodstream. It eventually makes its way to the brain to deliver the message that you are full and that you have a certain amount of energy available.
It sounds like the fuel indicator in a car. However, it could be called a fat regulator. It keeps the brain informed as to whether you are hungry and how much fat is currently in your body, just as the fuel indicator lets us know how much petrol is left in the tank.
Robert Lustig, a professor and obesity expert from the University of California, says, “leptin isn’t a fat hormone, it is a starvation hormone, made to signal the brain when we need to eat more”.
When leptin levels rise, your appetite depletes and you feel full. Your metabolic rate also increases and your brain thinks you have had enough food and fat to function. This then returns leptin levels back to normal.
It is at this point that food loses its appeal and doesn’t taste so good; this helps signal that you have eaten enough.
This process also sets your metabolism to normal, allowing you to eat normal amounts of food. However, when you diet and lose fat, you naturally produce less circulating leptin.
Consequently, as the levels of leptin fall below a certain level, your brain thinks you are starving and launches a number of initiatives to bring about a return to energy balance. The stimulation from the brain causes your appetite to increase.
Next week we will look at the other ‘fat’ hormone, ghrelin, and some ideas on how to power up the fat burners.
kathryn@maltanet.net