I believe that it's important for us to rethink our perception of weight
and dieting, and the health benefits of finding pleasure in eating.
Our beliefs influence the way our body responds to food – so, is it possible
that a simple change in mindset could help us to control our weight?
As a science writer researching a book on the mind-body connection,
I discovered that our thoughts about our food can shape our appetite
through multiple psychological and physiological pathways.
And by harnessing these 'expectation effects',
you may find a diet much easier to sustain,
with greater success over the long term. How can this be?
We have sensors in the digestive system that help to give us an idea
of how much food we have consumed, but our memories of what we have eaten,
and our expectations of its contents,
determines how the brain interprets those signals and,
as a consequence, our hunger later in the day.
Importantly, small differences in presentation, such as a food's label,
can influence those expectations.
In one experiment, participants were given a protein bar.
For some, it was labelled as a 'health bar containing
high levels of protein, vitamins and fibre'.
For others, the text described it as a 'tasty' treat
with a chocolate flavour and a 'yummy' raspberry core.
That labelling had a profound effect on the participants'
reported hunger after eating the snack.
People assumed that the 'healthy' bar would be less satisfying,
meaning that they found it less filling than a tasty treat.
They were even hungrier than people who had not eaten any snack at all.
Our mindset may even change our hormonal response to food.
In the early 2010s, Alia Crum, a health psychologist at Stanford University,
gave participants two milkshakes on different days.
Much like the test with the chocolate bars,
the nutritional contents of the milkshakes were the same,
but the participants saw different labels each time.
One label described the shake as indulgent, rich,
and delicious – 'heaven in a bottle' made from 'sumptuously smooth ice cream'.
They were told it had 620 calories in total.
The other label described it as 'light' and 'healthy' with just 140 calories.
Before and after the participants had drunk the shakes,
Crum took blood samples to measure the levels of ghrelin –
a hormone that stimulates hunger and typically falls after we've eaten.
She found that the labels, alone, shaped that response – the ghrelin rose
and then dropped much more drastically when the participants had seen
the 'indulgent' label emphasising the pleasurable aspects of the food,
compared with when they had seen the label emphasising its low-calorie content.
This is much closer to the response that you typically see after a satisfying meal.
The change in ghrelin may be especially important,
since the hormone can also reduce metabolism.
This means that expectations of deprivation could prevent your body
from burning as much energy, making your weight loss even harder.
These expectation effects do not end there.
Our attitudes can influence how quickly food moves
through the digestive system and even the absorption
of important nutrients like iron. If you feel like you are being deprived,
you may be getting less goodness from your food.
These findings have some important implications for dieters. They show that,
when we are trying to lose weight, we shouldn't forget the pleasure of eating.
Sure, we can try to find foods with fewer calories,
but we should try to make sure that they are packed with interesting
and exciting flavours that tantalise the taste buds.
We should try to create a greater sense of anticipation
before a meal, by visualising what we are about to eat.
And when the dish is served, we should make
a conscious effort to savour the enjoyment of every mouthful.
Finally, we should avoid a sense of shame that often comes
with the occasional indulgence, since it is rarely productive.
One of my favourite studies found that people who associate chocolate cake
with celebration were much more likely to meet
their dieting goals than those who saw it as a source of guilt.
By allowing yourself to enjoy the treat – you will be able
to offset those calories at a later point.
So, sometimes, it seems, we really can have our cake and eat it.