BBC SCIENCE FOCUS MAGAZINE COLLECTION 15DIETT
When it comes down to it, the science
of dieting is simple: eat less. You can
do it with a low-fat diet (like the raw
food diet), or a low-carb diet (like the
Atkins or paleo diet). But the problem
with diets is not so much losing
weight, but finding a way to do it that
is effective, safe, fits in with your
lifestyle and is sustainable so that you
don’t put the weight back on again.
Diet academics (as opposed to
product pushers) avoid prescriptive
advice because different diets fit
different people’s lifes t yles and
personalities. But recent research
indicates that one particular group of
diets is most effective for the greatest
number of people. These are the
super vised diet programmes, like the
Cambridge Weight Plan, LighterLife
and Optifast diets, consisting entirely
of prepared snack bars, shakes and
other food products. You might
assume these fast-acting diets would
be condemned by scientis t s a s dra s tic,
unhealthy and gimmicky. Yet research
is finding that these very low-caloriediets – also known as total food
replacement diets – are effective and
safe if applied correctly. A major
analysis of trials in 2017, headed by
Birmingham University’s Centre for
Obesity Research, showed that these
diets brought an average weight
loss of 10kg after 12 months. This
compares with research showing that
behavioural programmes (focused on
changing eating habits and exercising),
such as Slimming World and Weight
Watchers, bring a weight loss of 4kg
after one year.
Prof Jebb says that, although
research indicates that all dieters gain
weight afterwards (no matter which
regime they follow), the more weight
they lose the longer they stay beneath
the ‘obese and unhealthy’ bar. And
although food replacement diets may
look extreme, they do contain a
balance of nutrients that some
do-it-yourself diets might not.Verdict: Try a supervised diet to
safely shed excess weight.WHAT IS THE BEST DIET,
ACCORDING TO SCIENCE?
he statistics tell their own story.
One in four people in England
are now classified as obese,
compared with one in six in the
1990s. Fifty-eight per cent of women and
68 per cent of men are now overweight.
Being overweight makes us less healthy: a
study published in Lancet Public Health in
2017 showed a clear relationship between
hospital admissions and body weight. But
it isn’t just physical problems that are
the issue, because being overweight also
makes many people unhappy.
A British Social Attitudes survey
revealed that people who are overweight
suffer significant stigma and that 53
per cent of the British public believe
that most overweight people could lose
the extra pounds if they tried. But the
science shows that it’s not simply a matter
of being weak-willed.
“There are clear reward pathways for
food in the brain and so, if something is
rewarding and constantly available, why
wouldn’t you [seek more of it]?” says Prof
Susan Jebb, a nutrition scientist at Oxford
University. “You have to make a constant
conscious effort to say no.”
Fortunately, science is providing some
answers to the questions about weight
control. A decade ago, there weren’t enough
scientific trials to allow experts to provide
evidence-backed advice. Now, there are
clear scientific pointers on how to fight fat,
and what the studies find may surprise you.5GETTY