The new weight-loss math

[Guest guest]

It’s pretty simple: Since there are 3,500 calories in a pound of

body fat, eating 500 fewer calories each day – or burning them

off exercising – will lead to a slow and steady weight loss of a

pound a week. (The math: 500 x 7 days = 3,500)

According to U.S. researchers, this ubiquitous weight-loss rule

is overly simple and overly optimistic. And it can lead to

unrealistic expectations about how quickly you can achieve a

weight-loss goal.

The rule contends that cutting 200 calories a day from your diet

would lead to a loss of 20 pounds over the course of a year and

the weight loss should keep on going. But in reality that

doesn’t happen. Weight loss slows and eventually comes to halt

despite the drop in calorie intake.

This past weekend, at the American Association for the

Advancement of Science’s annual meeting in Vancouver, an

international team of researchers unveiled a new formula to

better predict how people will lose weight on a diet.

The 3,500-calorie assumption doesn’t account for how metabolism

changes during weight loss.

Your metabolism is the rate at which your body burns calories,

and it’s largely determined by how much muscle you have, since

muscle burns more calories at rest than body fat. Ultimately,

it’s your metabolism that dictates how easily you will lose or

gain weight.

As the body slims down, metabolism slows, causing it to burn

fewer calories at rest. A smaller body also burns fewer calories

during exercise. The net result: a sluggish rate of weight loss

that can frustrate dieters and cause them to abandon their plan.

Now health-care professionals and researchers have a tool to

more accurately predict a dieter’s expected weight loss over

time, based on changes to metabolism. Having a more realistic

sense of what to expect can help people stay motivated over the

long term.

The new formula and accompanying web-based model were developed

by researchers from the U.S. National Institutes of Health, the

World Health Organization, Columbia University and Harvard

School of Public Health,

The online tool – called the Body Weight Simulator – requires

people to input their age, gender, body weight, height, activity

level and weight goal (http://bwsimulator.niddk.nih.gov).

It then simulates what diet and exercise changes are required to

reach the goal weight and what changes are necessary to maintain

it over time.

Using this model, the researchers found that people’s bodies

adapt slowly to dietary changes.

For example, the average overweight person needs to cut 100

calories from their current intake per day to lose 10 pounds

over three years.

Half of the weight will be lost in one year and then you’ll

reach a plateau, slowly losing the remainder by three years.

In contrast, for the same calorie reduction, the 3,500-calorie

formula predicts you’ll lose 10 pounds in one year – and 30

pounds by three years.

The Body Weight Simulator isn’t aimed at consumers. It’s

intended to be used as a tool for doctors, dietitians and

researchers to re-evaluate client goals and identify necessary

diet and exercise changes to achieve a weight loss goal at a

realistic pace.

The online tool also highlights a salient point: Even though

weight loss slows down over time, you will continue to lose

weight if you stick to your plan. That’s a positive message for

anyone trying to lose weight.

It also emphasizes the need to abandon our quick-fix mentality.

Permanent weight loss takes time and requires persistence,

consistency and patience. Not easy, I know.

There are other reasons weight loss slows down that have nothing

to do with metabolism. They’re related to human nature and

they’re within your control.

If you’re experiencing a slowdown, the following strategies can

help you pick up the pace.

Don’t let lapses accumulate.

You’re bound to fall off plan occasionally. Losing weight is not

an all-or-nothing endeavour.

If you slip, don’t tell yourself “I’ll start again on Monday.”

Instead, get back on track, the sooner the better. One small

lapse won’t make a difference to the scale.

Rein in portion sizes.

It happens gradually. Instead of one cup of rice, you’re serving

yourself 1.5 cups and an extra 100 calories. The chicken breast

that not long ago was a precise four ounces, now weighs in at

six ounces.

A few extra calories here and there add up and can make the

difference between losing and holding steady. If this sounds

familiar, measure and weigh your foods again.

Be mindful of extras.

An extra dessert, a few tastes while making dinner, a bite or

two off your kid’s plate. Those extra calories can – and will –

stall weight loss.

Twenty pounds ago you could get away with eating something extra

here and there and still lose weight each week. But not any

more. Keep in mind that smaller bodies burn fewer calories, so

you have less leeway than before.

Resume keeping a food diary to see if extra calories are

sneaking into your diet.

Be consistent on the weekend.

Larger meals, alcoholic beverages, and a few extra snacks on the

weekend can cause the needle on the scale to jump Monday

morning. You play catch-up during the week to lose those few

pounds. Then the following weekend, you put a couple more back

on. The end result: no progress.

If weekends are your trouble spot, keep a food diary Friday

through Sunday.

Beck, a Toronto-based dietitian at the Medcan Clinic, is

on CTV’s Canada AM every Wednesday. Her website is

lesliebeck.com.