2020-03-07 New Zealand Listener

22 LISTENER MARCH 7 2020

CONQUERING THE KILOS

I

n a chicken and egg sense,

we may have been looking

at exercise the wrong way.

New studies suggest that

perhaps we don’t move

enough because we’re too

heavy, and once we’re lighter,

we suddenly feel like it. A

reputable study reported in Dr

Michael Greger’s How Not to

Diet has found, albeit for rea-

sons still not well understood,

that once they lose a certain

amount of weight, people are

more likely to become more

active, to the point of taking

deliberate exercise.

Exercise has had a bad rap

with the anti-obesity frater-

nity, partly because of people’s

tendency to “eat up to” their

activity levels and beyond and

to unconsciously reduce their

ambient activity on exercise

days. People frequently over-

report their exercise durations,

and repeated studies have

shown that a workout gives a

high proportion of people a

misleading sense that they’re

able to eat more without gain-

ing weight.

Constant new research

factoids, by turns bewildering

and encouraging, give different

perspectives about the optimal

intensity and duration for

weight loss. The only consen-

sus seems to be that pretty

much any form of exercise

or added physical activity is a

health bonanza, but only either

prolonged or intense regular

exercise makes a significant

contribution to weight loss.

However, exercise has passed

the high bar of being a star

on Greger’s list of weight loss

accelerant “tweaks”.

His bottom line: “You have

to do it for an hour for it to

make any real difference.”

And as vigorously as you can

manage it, he adds.

He says very few people

make that commitment, but

there are several reasons they

should. At the very least, exer-

cise appears to be valuable in

keeping weight off once it has

been lost.

Australian obesity academic

Nick Fuller, who visited New

Zealand recently publicising

his work on beating weight-

loss plateaux, endorses this. “I

make no apology, because it is

so important. The people who

have successfully lost weight

and kept it off [for more than

five years] are those who eat

a large volume of whole-

some food and perform a lot

of daily activity.” His book,

Interval Weight Loss, has the

same key messages as Greger’s,

including “move a lot.”

E

xercise is more efficient

than diet at getting rid of

the deadliest “brown” fat,

which accumulates around

abdominal organs. One of the

main reasons people strive to

lose weight is to avoid dying

from “brown” fat. Even slim

people can have too much

of it. Greger cites specialists’

observations that for many

life-blighting conditions, exer-

cise would do more for them

than medication, but they’re

often not told this.

But exercise can also be a

multi-pronged fast-tracker

to losing weight. First, done

after several hours’ fasting –

for example, before breakfast

or dinner – an hour’s brisk

exercise causes the body to

start right in on burning stored

body fat, rather than stored

glucose, because the glucose

tank is nearly empty.

Second, done for long

enough and vigorously

enough, it causes the body to

burn more energy for up to

48 hours afterwards, not just

during the activity itself.

Third, it’s been found that

the will to exercise often kicks

in after a certain amount of

weight loss, given a switch

to a good diet, he says. In

one study, some people were

given a diet high in saturated

fats and others one low in

saturated fats. Activity tracking

found that 90% of the latter

group ramped up their exercise

by 12-15%. The researchers

couldn’t explain why but

postulated that a high satu-

rated-fat intake might dampen

our desire to be active.

B

ut perhaps Greger’s most

arresting finding is the

role played by non-

exercise, activity-wrought

thermogenesis. It’s what hap-

pens in studies where people

are deliberately overfed: they

start moving more, even if

they’re not conscious of doing

actual exercise. When a con-

trol group was overfed 1000

You’ve got to

move it, move it

People who have lost weight

and kept it off for years tend to

have one thing in common.

“Continuous high

intensity beats

lower intensity,

but short bursts

of high intensity

do not beat

continuous,

moderate-

intensity exercise.”

Way to go: only either

prolonged or intense

regular exercise

makes a significant

contribution to

weight loss.

GE

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