• Plateaus in fat loss arc common and are due to physiological adjustments and reversion towards old habits.

• Maintenance of fat loss can be extremely difficult due to changes in metabolic rate and body composition.

• Physiological adjustments result in a lower than predicted loss of body fiat with changes in energy balance.

• Adaptations include decreases in metabolic rate, changes in body composition, changes in fat utilisation and modifications of food intake.

• Long term maintenance of fat loss is highest amongst those who exercise regularly, change lifetime eating patterns and have well-developed stress management techniques.

• Plateaus may be countered by change.

As most perennial dieters will tell you, it’s easy to lose fat, but keeping it off is another matter. If fat losses continued in direct proportion to the initial energy deficit (i.e. energy in minus energy out, as proposed in earlier models of fat loss), there would be a steady decline towards a goal given a constant deficit in energy balance, but this is seldom the case. There is an initial significant loss, then the rate of decline decreases until a type of ‘plateauing’ occurs followed often by a return to baseline levels. The challenge is to determine why this is so and if and how this can be modified.

Undoubtedly part of the reason for plateaus and regain is a return to previous habits. People tend to start fat loss programs with great gusto and commitment, but after 3 to 6 months their exercise and dietary habits tend to start slipping back. This is common and understandable given the environment of high-fat foods and labour-saving devices they face. To swim against this environmental ride takes effort and the effort is greater for those more genetically predisposed to obesity. It is not surprising that the effort fades with time. People often find it difficult to admit to a return to old habits and seek metabolic explanations for their plateaus. In truth, for most people the plateaus are due to a combination of behavioural and metabolic factors.

The extent to which metabolic changes slow down fat loss is a matter of some considerable debate. In 1950, the US nutritionist Dr Ancel Keys, wrote: It might seem entirely reasonable that the energetic processes of the body diminish in intensity as the exogenous food supply is reduced. It is reasonable in the sense that a wise man reduces his expenditure when his income is cut.’ This survival tactic has been well-described in animal models of obesity. Studies at Cambridge University on a particular species of desert mouse for example, have shown that when compared with a ‘dry mouse—or one accustomed to plenty of food—the desert mouse is able to adapt to decreases in body weight caused by lack of sustenance by simply slowing down its metabolic processes. Humans have less facility to actively alter metabolic processes to match changes in food intake, although adaptations do certainly occur.

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• Fat cells are similar to other cells, but contain a lipid or fat pool for storage of fats to be used as energy.

• The average human body has 30-50 billion fat cells, and obese people have up to 100 billion.

• Most increases in fat mass are associated with increases in fat cell size.

• Lipogenesis refers to the storage of fat in fat cells; lipolysis the breakdown of fat.

• Lipogenesis and lipolysis are controlled by a number of enzymes and hormones.

• There is a constant cycle of fat storage and breakdown at the fat cell level, but increases in lipolysis do not translate into increases in fat burning.

• The state of energy balance j| the major influence in the lipogenesis/lipolysis cycle.

A fat cell (adipocyte) is similar in form to many other types of body cells with the exception of its storage ‘depot’—a lipid (fat) pool, which can make up to 90 per cent of the cell. Otherwise, the adipocyte has a cell nucleus, with all the ‘head office’ functions and genetic materials of other cells, and the cytoplasm (the ‘jelly’) and mitochondria (the ‘powerhouse’) characteristic of skin, bone and other organ cells.

The average fat cell stores around 0.5 micrograms of fat in its lipid pool (a microgram is a millionth of a gram) and the average, non obese individual has between 30-50 billion of these fat cells throughout his/her body (in fact more on her than him, as you’ll see below). Doing the sums on this, you can see that the average person will be carrying around 15kg of fat as his/her ’spare tank’, or energy reserve.

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Alice, a 42-year-old New York City resident, didn’t always have a daring palate. Growing up, she feasted on lots of pizza and sugar. “My mother’s idea of a treat was a box of brown sugar cubes, a chocolate bar, or a can of ready-mixed frosting,” she says.

Alice’s unhealthy food choices caught up with her during her teenage years, when she started gaining weight. Her eating habits didn’t improve as she got older, either. A typical day featured a sugary cereal for breakfast, a bulky sandwich for lunch, and dinner in a restaurant, where she’d eat to the point of discomfort.

By her late thirties, despite bouts of yo-yo dieting, Alice had reached 235 pounds. Her waistline wasn’t all that suffered. Her back ached due to her weight, and her self-esteem tumbled.

“My breaking point came when I had to go away for a weekend and I ordered several new outfits for the trip,” she says. “I didn’t try on the clothes before leaving, and when I got to where I was going, I discovered that nothing that I had bought fit.”

Hurting physically and emotionally, Alice knew that she had to slim down. Over the next year and a half, she made a modest effort to improve her eating habits, which led to a 23-pound weight loss:

At that point, she felt that she needed a program with structure, so she joined Weight Watchers. Her group leader introduced her to international foods that made her meals more exciting and healthy.

Alice enticed her tastebuds with ethnic favorites that she found in cookbooks: tabbouleh, a minty wheat salad from the Middle East; couscous, a pebbly pasta from northern Africa; and polenta, a corn-brea’dlike food flavored with roasted red peppers and tomatoes that’s popular in Italy. Along the way, she learned how to cook with the salsas and spices that flavor many ethnic cuisines. “The new tastes transformed my palate,” she says. “Now, when I take even a bite of the some of the foods that I used to eat, I don’t like them.”

Alice had so much fun experimenting with exotic new recipes that she never felt like she was dieting. Yet she lost 44 pounds in less than 6 months, reaching her personal goal weight of 168 in December 1998. And she has held steady ever since.

Alice says that she seldom visits her chiropractor for her aching back anymore. And she feels much stronger emotionally, now that her self-esteem isn’t bogged down by extra weight. “Since I’ve slimmed down, I’ve gotten my hair cut and styled differently,” she says. “Many people don’t even recognize me, which is fun.”

WINNING ACTION

Explore the world via your dinner plate. Some of the healthiest low-fat meals come from other cultures. Tempt your tastebuds with Greek souvlakia (lamb served

on skewers), French ratatouille (a vegetable dish cooked in olive oil), Japanese yakitori (grilled chicken), Thai ginger beef, or Indian mulligatawny (a kind of lentil soup). These are just a few examples of the “world’s fare” that can please your palate without widening your waistline. Consider investing in an ethnic cookbook such as The Mediterranean Diet Cookbook, Step-by-Step Indian Cooking, or Steven Raichlen’s Healthy Latin Cooking.

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