The main way of counteracting the adaptive reductions in energy expenditure is through physical activity. This has been shown in several studies to counteract the energy sparing effects of dietary restriction. It does this by increasing energy expenditure both during and after exercise and by maintaining lean body mass. Studies examining exercise, however, have not always been convincing, possibly due to the difficulty in getting people to comply with the exercise regimens that have been set for them. There is still enough evidence to suggest that exercise can help with those who do comply and indeed may be the most effective form of continuing fat loss in the maintenance stage. There is little argument amongst scientists that diet appears to have the most immediate effect on fat loss, but it is now also becoming increasingly clear that exercise should be the mainstay in any fat loss maintenance program

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roaming the streets on their own, or joined by a team manager. Triglycerides cannot get directly into the fat cell because their molecules are too big, so the team needs to be broken down into FFAs and glycerol units like the footballers having to pass single file through the door into a nightclub. Once inside the nightclub (fat cell), they join up with the glycerol into a ‘team’ again and are stored as TGs.

Keeping the nightclub analogy, our footballers have to get past a doorman. In the fat cell, the main ‘doorman’ is the hormone insulin, which is formed in the pancreas and secreted into the bloodstream in response to a rise in blood sugars. Before a meal (low insulin), the doorman has the exit open allowing FFAs to leave to supply energy for the body. After a meal (high insulin), the doorman closes the exit and opens the entrance to allow FFAs to enter. Insulin also activates an enzyme, lipoprotein lipase (LPL) in the fat cell. This acts like a ‘spruiker’ outside the nightclub touting for business. Adipose lipoprotein lipase (ALPL) breaks FFAs off the TG so that they can enter the fat cell.

Insulin also acts as a doorman for the muscle cell but here the functions are somewhat different because he has two entrances to control. Before a meal he has the ‘fat door” open to allow FFAs into the muscle cell to provide it with energy. He also activates muscle LPL which breaks down the TG teams passing by to allow FFAs to get through the door. After a meal, he closes the fat door and opens the ‘glucose door’ so the muscle switches from running on fat to running on glucose. (Interestingly, if the muscle needs a lot of energy such as during exercise, the glucose goes straight in through another door that insulin has no control over.)

Basically, when the body needs more energy than is currently available from food, triglycerides in the fat pool are broken down into FFAs plus glycerol and sent to the muscle via the bloodstream to help out. It’s as if someone has run into our ‘nightclub’ and called all the footballers out to help out in another building down the road. The process is triggered by another enzyme which, like all enzymes, causes a reaction but doesn’t take part in that reaction. Hormone Sensitive Lipase (HSL) is the enzyme involved in this removal of fats from the fat pool. It does

so under orders from a range of chemical ‘alarmists’ in the bloodstream, particularly the catecholamines, or hormones secreted from the adrenal glands at the top of the kidneys. The catecholamines, therefore, facilitate lipolysis, but inhibit lipogenesis. Insulin, on the other hand, facilitates lipogenesis, but inhibits lipolysis.

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A native of Louisiana, Robin was raised on a traditional “Southern diet of fried and gravy-smothered foods. Eventually, she turned her love of food and her talent for cooking into a successful career as a certified dietary manager, supervising the kitchens of restaurants in her home state.

The problem was that Robin got in the habit of taste-testing while she worked—whether or not she was hungry. And when she got home, she’d sit down to a traditional meal with her family.

Constantly being around food proved disastrous for Robin. By 1998, she was just 7 pounds shy of 300. And she was miserable.

Robin knew enough about nutrition to realize that she was not eating out of need. She was eating out of habit. A habit fed by being around tasty, delicious food all day—especially cakes and pies, since pastries were her specialty She realized that she had completely lost touch with her internal hunger cues.

Robin’s weight-loss strategy turned out to be one simple promise that she made to herself. “I told myself that I would eat only when I was hungry and that I would stop when I was satisfied—not stuffed, just satisfied,” she explains. This forced her to listen to her body and think about why she wanted to eat before she put food in her mouth. “If I realized that I wasn’t truly hungry, I’d distract myself until the impulse passed—usually by thinking about the pounds I’d gain if I gave in,” she says.

By adjusting her eating pattern and making healthier food choices, Robin was able to take off 102 pounds in about a year. She’s

still working to reach her goal weight of 149 pounds. And she says her conviction to lose weight is stronger than any urge to eat. “I felt an overwhelming desire to overeat only once,” she notes. “Reminding myself of my goal and focusing on my success so far is what keeps me on track.” •

WINNING ACTION

Listen to your body. Like Robin, I’ve learned to distinguish between when I’m actually hungry and when I’m just responding to the sight of tempting foods. It has made a huge difference in helping me keep my weight under control. Here’s a trick that I find helpful. Before eating anything, ask yourself, “Am I really hungry?” Rate your hunger on a scale of zero to five (zero being the least hungry, five being the most). Let your body tell you how much to eat.

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