Effects of weight Andrew M Prentice, Peter R Murgatroyd,

“yo-yo” lean

It is frequently dieting,

causes

mass

(LBM).

body

population an annual

Data

are

Data

weight permanent

are presented

presented

from

British

women

obese

cycles of VLCD-induced The proportion of weight dicted. weight

that and

from

weight loss lost as LBM

an

young animals, metabolic are not mediated through

Am

KEY WORDS

and was

1 8-wk

prospective relapse. than pre-

J C/in Nutr

fat, lean

of

effects body

in

l992;56:209S-l6S.

cycling,

body

these

mass,

yo-yo

would

exacerbate

vicious

cycle.

the The

tendency

“dieting

attractive

for not

paper

examines

is frequently

far exceeded

energy

evidence

from

dieting,

body diets,

and

studies

in normal

human

changes manner

in lean during

and fat tissue both positive

that

the extensive

and

occur and

many

its supporting relating

weight

1) It argues to cope weight

with

cycling.

manipulated

that

a

people

As with

hence

have

volunteers

set up

is regularly

by obese

evidence

balance

body

demonstrate

that

in a concerted and predictable negative energy balance. 3) It

published

duced weight cycling in animal ofa recent study ofexperimental

very-low-calorie

cited

has scientific

and

theory

programs.

the

weight

summarizes

weight fat”

changes in body composition. tissue has specifically evolved

of fluctuating

2) It cites

you

treatment

its influence

cycling to long-term that human adipose periods

and

entering

theories

to regain makes

by the lay press

as a reason evidence. This

three

from experimental a high level of con-

health, alterations

A Coward,

reinforced

by was

underwent

subsequent no greater

efficiency, and permanent

Weight

body

African

does not significantly alter body composition. although weight cycling may affect growth

sensus that cycling We conclude that,

position,

or

loss of

a rural

who

A review of the published results cycling in small animals also shows

composition.

cycling,

profound weight cycling caused No detrimental effect on LBM

also

of moderately

claimed

an inappropriate

that undergoes hungry season.

observed. study

A Jebb, Gail R Goldberg, William D Poppitt, and Timothy J Cole”2

data

models. yo-yo

on experimentally

in-

4) It describes the results dieting in obese women.

comVLCDS

The evolutionary origin significance for weight

of adipose cycling

tissue

and

its

Introduction The functional Weight the battle (1-3).

cycling, or “yo-yo” dieting, is a common feature of that obese people wage against their excessive fatness

It may

diet

be particularly

common

users

VLCDS

(VLCD)

because

among have

very-low-caloriea proven

ability

achieve natural

rapid weight loss but do nothing to counteract tendency to return to its prediet weight and

Indeed weight

many regain

they

VLCD users resign themselves is inevitable and resort to bouts

perceive

their

weight

to have

to

the body’s adiposity.

to the fact that of dieting when

returned

to an

A number

of publications

suggested

rimental eters.

effects With

that

in both

frequent

regained

consists

is primarily

on the subject, Cannon and makes you fat.” The theory olation

of the

findings

of the

a subgroup ofthe in adiposity as soon

increase to food

after

the controlled

1). If correct, body

mass

the theory (LBM)

accompanied Am iC/in

with

by a permanent Nuir

l992;56:209S-16S.

health

it has

ofboth fat.

been

this extent

cycle

Printed

study

of the study

loss.

This

in metabolic in USA.

has variously

sexual

been

signaling,

and

subjected to periods of acute food shortages or winters and due to crop failures. Many world are still affected by such fluctuating

2 illustrates

child-bearing age Gambia, in which ofenergy

the weight

changes

man’s hunterbeen regularly

during dry communities food supplies.

recorded

seasons in the

in women

of

in the rural African village of Keneba, The we have been conducting longitudinal studies

regulation.

In this community,

weight

which to run

cycling

is caused

occurs when the previous out and before the current

year’s harvest (6). In the early years ofour studies, corresponding to the Sahelian drought, the average peak-to-trough fluctuation was close to 6 kg, with many subjects showing much larger swings. Previous studies in Keneba confirm that the hungry season

has

occured

for

40 y. Average

fat mass

assessed

by deu-

a significant free access

a cumulative

of weight

decrease

as “dieting on extrap-

semi-starvation

phase

book

tissue

insulation,

by an annual “hungry season”, year’s food supplies have started

proposed

popular

volunteers exhibited as they were permitted predict

detparam-

fat and lean tissue

In their

Minnesota

rehabilitation would each

and

Einzig (4) described is based to a great

(5) in which

long-term

ofadipose

in thermal

to the most powerful selective pressures. Modern gatherer and pastoralist antecedents would have

Figure

and lay press

have

composition

dieting

weight

may

of physiological

to body

lost during

the scientific

dieting

on a variety

respect

that weight but

that

significance

to its role

energy buffering. We believe the final explanation to be most likely because it is closely related to survival and would be subject

intolerable

level. have

attributed

(Fig

I

loss of lean

UK.

would rate,

be

which

© 1992 American

2

From

the MRC

Dunn

reprint

requests

Address

trition

Centre,

100 Tennis

Society for Clinical Nutrition

Nutrition

Unit,

Milton

Road,

to AM Prentice,

MRC

Dunn

Court

Road,

Cambridge,

CB2

Cambridge, Clinical IQL,

Nu-

UK.

209S

Downloaded from https://academic.oup.com/ajcn/article-abstract/56/1/209S/4715687 by guest on 20 November 2018

ABSTRACT

Susan Sally

cycling on body composition1’2

21 Os

PRENTICE

18

ET AL to grow

in both

thereafter

there

women

I Semi-starvation

Rehab

the weight 25 y these

Ad tib

12

10

curve,

20

10

30

that

40

the Gambians

with

of pregnancy likely that

50

weight

trivial (7).

body

and

nonsignificant

Thus,

an average

stores

each

subgroup

water

ofthe

measurements

seasonal

woman

fluctuation

was cycling

women

also

indicated

in lean

body

50-60%

was a mass

of her fat

year.

cycling

this

seasonal

weight

cycling

causes

a more

rapid loss of lean tissue with aging than occurs in noncycling populations. we analyzed cross-sectional data on body composition in both men and women in Keneba. In this analysis body fat was assessed from measurements of four skinfold-thickness sites

and

assessed

the equations

of Durnin

and

by subtracting

fat mass

from

ofpredictive applicable but not

equations to Gambians

derived with

A potential from

difficulty

cross-sectional

Womersley

(8).

total

mass.

body

of a constant offset of within-population

in assessing data

is that

longitudinal the

result

may

have

low

analysis of variance in the weight-cycling British remarkable

to endure

in high-quality

undergo

subjects in view

harsh

and

in view

cycles

which add a further stress. It seems of a high LBM is at least partly

LBM

The

may

and

trends

not

have

a detrimental

a closer examination in Figure 1 shows that

been

transient.

effect

on lean

average weight

58 wk after

In a smaller

likely

the

start

group

of eight

of rehabilitation,

was

use

value of body fat equal to 102 per cent of the control.”

that

to be broadly

man’s

the

nutritional

phylogenic

I 10 per

cent

situation

representative

and

in the

of the

and

that

time-scale,

should still possess therefore be benign.

should trends.

in LBM

The composition regain fat and

it seems ability

of weight

An appreciation regain

this

and

loss

logical that

during

of the fact that it is quite lean

tissue

that

simultaneously

weight normal when

82

83

84

85

86

87

Year

in body weight

have

under

such

loss

body

47

age.

is

that

cycling

48

fluctuations

Gambia

modern

weight

a

ofchild-bearing

body

Because an abundant and reliable is a very recent phenomenon on

50

FIG 2. Seasonal

the

conditions

development,

any detrimental consequences. food supply in Western society an evolutionary

be confounded

81

subjects

body

49

80

tissue.

of the Minnesota data the increase in adiposity

51

in women

of

repeated

52

79

(P

nutritional

protein,

constantly

53

78

in

the age of are too small

fat was only 1.22 kg greater than at baseline and the difference was not significant. The authors commented (5): “At R58 the return towards pre-starvation values was nearly completed, with the

molded

by secular trends in weight and height. Inspection of the Gambian data in Figure 3 reveals the following features: young men continue

.c

their

U shape

conditions. there will have been a strong selective drive in favor of individuals who can successfully expand and contract their adipose energy reserves in times of feast and famine without

in Caucasians may not be entirely different body fat distributions,

any error is likely to consist detract from an examination

a diet

the women

does

Furthermore, summarized

We believe

To test whether

inverted

is < 3 kg. After

have

and lactation, the maintenance

remeasured

in a representative

young

up until

related to the high levels of physical activity in The Gambia. Whatever is the true explanation it is quite clear that the annual

(weeks)

regain of body fat after derestriction from 24 wk of in the Minnesota Experiment. Follow-up data after a period eating were only available for 12 ofthe 32 subjects (5).

Total

and

in rural Gambian

women.

Plot derived

from over 20 000 measurements

88

man should

and

to lose and weight is

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fact

of the fact that

121

_

FIG I . Excessive

dilution

magnitude

the

Time

1 1 kg (7).

the

4

0

terium

but

is a significant

Gambian subjects than in the noncycling < 0.01 for both sexes). This is somewhat conditions

libitum

there

y old, but

trend;

but not height

6

In

ofad

to gain in weight

thereafter

they are 25

of a secular

with increasing age. Contrary to expectations, showed this decline to be significantly slower

8

2

semistarvation

until

evidence

secular trends in both weight and height to significantly confound any age trends in LBM particularly if LBM is expressed as a percentage of total body weight. Figure 4 shows the effect of aging on percent LBM in the Gambian subjects compared with the nonweight-cycling Caucasian subjects. Both groups show a pronounced decline in LBM

14

0

and

and weight

is little

continue

mid-20s 16

height

WEIGHT

CYCLING

AND

BODY

COMPOSITION

211S

Weight

Height ‘U

IOU

44 60

170 E

.c

0i

I

a

a

50

160

1womenl IWomeni

39

IJU

10

20

30

40

Age

FIG 3. Secular for men

altered

is critical

50

trends in height and weight in Gambian

adults assessed

to an understanding

imental widely

analysis by the addition of a substantial found an excellent degree of concordance In summary, Forbes (9) demonstrated

cycled animals

of the effects

that

are to remain

a lean

higher

person

proportion

ratio is predicted 10 kg of body 0.6. Both Forbes under most very similar

close The

expresses the ratio In an obese person

loss. The

of new data and (10). that there is a strong

body

between lean and fat mass in individuals gains or loses fat they must also alter their

composition.

to the curve

lean-to-fat

significance

dictable thus composition

cycling

on body

composition

±

SE; n

survey. i

would

be predicted

oflean

tissue

would

as #{212}LBM:#{212}BW (where with 30-40 kg of body

of this analysis

in animal

lose a much

a fat person. BW is body

in small

use of between

1 and

ferent cycled

variables. Some until they reach

outcome animals

Forbes

with to be that

it demonstrates

are and

un-

change when body weight the changes are highly pre-

70

270

=

this

in body or ab-

and

of weight a number

cycling of exper-

original

and

cycles,

(1 1-24).

These

mature

animals,

the

and a variety

of dif-

ofthe studies refeed the weightthe same body weight as nonthe total food intakes to the weight-cycling

publications

include

impressive

in all group.

weight

manipulations to which the provide a wealth of inforseto

paper.

Table 1 summarizes the effects of weight body fat in eight different studies representing

if the “dieting Similarly,

cycled

and

makes you fat” Table 2 summarizes

noncycled

the exception

information studies

as a result

within-study

ofthat

by Gray

of using

ofweight

be remembered

that,

in Tables

2 at least

dude evidence

1 and

only

one

at the

which

P

effect

strains

results. that

reported

on LBM

would

< 0.05 ofbody

in

provides

differ widely

and

in the 2 1 comparisons

result

gross estimates

for a detrimental

one

cycling

LBM

are the same,

of different

by definition,

difference

that these

values ofexpressing

reveal

effect

cited

et al (16),

animals

modes

comparisons

true. on percent

The studies

The absolute

ofdifferent

significant

theory were the data

animals.

on LBM.

and as a result ginally

cycling on percent all published in-

ofwhich we are aware ( 1 1- 19). In none ofthese studies a significant increase in body fat as would be expected

was there

with

vary

on alterations in metabolic efficiency, macronutrient and body composition. Only the latter are pertinent

a significant

animals

14 restriction

controls and others match but supply it intermittently

weight). fat, the #{212}LBM-#{212}BW formation

the effects

developed

ofgrowing

mation lection,

such

models

easy to investigate

use

“normal”

composition changes in both weight gain

is that

been

the

of the

to be O.2-O.3. In a very lean person fat the #{212}LBM-#{212}BW ratio is predicted (9) and Prentice et al (10) demonstrated

lean tissue should direction and that

have

include

indicating the very profound are subjected. These studies

is curvilinear

to gain and

than

paradigms and

Many

allowing us to assess whether any changes that occur with weight cycling are normal

It is relatively

by cross-sectional

curves animals

normal.

Weight

60

(years)

and that lean tissue

representing

relationship

circumstances actual body to the predicted changes

equivocally that changes in either

50

and 443 for women.

of weight

if they

40

Age

on body composition. Forbes (9) presented an elegant of the relative changes in lean and fat mass that would be anticipated if body composition is to remain within normal limits during fluctuations in weight. We recently updated this

body

30

(years)

cycling analysis

relationship ifa person

20

10

60

be expected

no

between and

age

However, a marit should

listed to yield

level. We therefore concomposition provide no

of weight

cycling.

Downloaded from https://academic.oup.com/ajcn/article-abstract/56/1/209S/4715687 by guest on 20 November 2018

U

PRENTICE

2 12S

ET AL

Men

Women

100

90

a

90 Gabia

0 .0

80

mia

U) U)

a

E 70

70

Britain

>1

0 0 .0 C

a a

60

60

-I

Britain

20

10

30

40

Age

50

60

70

Several composition tein

sexes)

from

Durnin

and DNA Liver weight

(9-1 5 wk-old) lean (L) and

and mature rats. obese (0) animals

and noncycling

populations.

Effect

I of weight

cycling

on body

fat content

i

±

50

60

70

(years)

SE; British data (n

481

=

for

ad /ibiium (AL and AO) or were intermittently restricted (RL and RO) over four cycles. In the young animals, liver weights expressed as a percentage ofbody weight were AL 2.26% versus RL 2.26% (NS); AO 3.03% versus RO 4.62% (NS). In the mature animals the results were AL 2. 1 8% versus RL 2.38% (NS); AO 3.65% versus 3. 1 5% (P < 0.05). Only one

either

=

Cleary

(20,

21)

=

In both studies that were fed

=

of experimental

=

=

=

=

of these

TABLE

40

(8).

information on body in some cases the pro-

content of the tissue. has been reported in five studies.

studied growing she investigated

30

Age

and Womersley

studies provide more detailed by giving organ weights and

20

(years)

FIG 4. Effect of aging on LBM in weight-cycling combined

10

differences

was

marginally

significant.

There

were

no

TABLE

animals

2 Effect of weight

cycling

on LBM

of experimental

animals

% B ody fat % L BM Source

Cycles

Control

P

Cycled

Source Bjorntorp and Yang Walksetal(l2) Brownelletal(l3) Hill et al (14) Hill et al (l5)* A

( 1 1)

B Grayetal(l6) Desautels and Dubs Turk (18) Male Female Wheeler et al ( 19) C

A, immediately

further

l8-d ad libitum

( 17)

1 1 2 4

6.3 14.6 33.1 12.4

6.6 16.5 28.2 13.0

NS NS NS NS

4 4 2 14

6.6 10.2 23.8 7

7.1 11.7 22.4 7

NS NS NS NS

5 5 3 after

completion

feeding.

11.2 12.3 1 1.8 of four

weight

11.5 13.8 1 1.8 cycles;

B, after

NS N5 NS a

Bjorntorp and Yang Walksetal(l2) Brownell et al (13) Hill et al (14) Hill et al (l5)

(1 1)

A B Desautels

and Dubs

(17)

Turk (18) Male

A, immediately

further

l8-d ad libitum

Control

Cycled

P

1 1 2 4

2 1.5 17.8 13.2 23.1

20.6 17.7 14.9 22.1

NS NS NS NS

4 4

23.8 20.8

22.7 22.3

NS NS

26

26

NS

20. 1 19.3 14.9

20.0 18.0 16.1

14 5 5 3

Female Wheeleretal(l9) C

Cycles

after completion feeding.

of four weight cycles;

NS