Unfortunately, cigarette smoking really is an aid to weight management. Here is how it works and why it is so effective: Nicotine can reduce your desire to eat by directly affecting the activity of serotonin and dopamine, which are substances that control neural transmission in areas of your brain that turn your appetite on and off. Nicotine elevates the activity of these substances in a way that is somewhat similar to what happens when you eat a piece of candy; for a certain period after smoking a cigarette or eating that candy you feel less hungry.
Nicotine causes your adrenal glands to release catecholamines which in turn cause the liver to release glucose into the bloodstream and your fat cells to release fatty acids. This increases the energy available to all the cells of your body, and the reaction is similar to what happens after you eat, which also may help reduce your appetite.
The catecholamines are stimulants and they cause your metabolic rate to increase sharply within seconds after you begin smoking. The increase appears to be even greater during physical activity than when you are sitting still. If you smoke a pack or a pack and a half of cigarettes each day, your daily energy needs can be increased by about 200 calories. Some experts believe that a good part of this increase is due to the higher rate at which those fatty acids keep circulating in and out of your fat cells each time you smoke. That is, out come the fatty acids at the onset of smoking, and then back they go into the fat cells in between cigarettes. This work requires energy.
But there are a couple of even more insidious/actors at work that can lead to weight gain when you quit smoking even though you don’t eat an ounce more of anything. In fact, these factors can lead to weight gain even if you go on a reduced-calorie diet after you quit.
First, nicotine can cause an increase in the activity of the enzyme adipose tissue lipoprotein lipase (AT-LPL), which is responsible for incorporating fat into your fat cells. This appears to be a counter-regulatory reaction and it’s likely that the more you smoke, the greater the increase in this fat-storing enzyme.
Because nicotine increases metabolic rate and keeps pulling fatty acids from your fat cells and burning them up each time you smoke a cigarette, smoking can result in your being from 10 to 12 pounds, or even more, below the natural weight where you would be as a non smoker. Your body tries to compensate for this nicotine-induced fat burning by working extra hard, increasing AT-LPL activity, to get what fat it can from your diet into your fat cells. The increased cycling of fatty acids in and out of your fat cells in between cigarettes may also stimulate heightened AT-LPL activity. The extent of AT-LPL activity may be related to the amount smoked: The more you smoke, the greater the cycling, and the greater the AT-LPL activity.
When you stop smoking, the heightened activity of AT- LPL1 can make fat incorporation much easier than if you had never been a smoker. Your hungry fat cells are just lying in wait to suck up the fat in your diet, in order to make up for the depletion that they have endured due to nicotine.
