Does it matter what time I eat?
Don't eat carbs! Don't eat protein!
Ok, actually some protein,
but then don't eat fats.
Unless…
Unless, they're the type of fats that are good for you.
It's like what?!
I've had enough. I've had enough. I've had enough.
I need a break from all this confusing and contradictory advice about what to eat.
What I want to know is, even if I don't change what I eat,
but then I change when I eat,
can I improve my health that way?
So can just changing my mealtimes actually make me healthier?
Now, this experiment looked at the effect of eating breakfast
an hour and a half later than you normally would in the morning,
then eating dinner an hour and a half earlier than you normally would in the evening,
meaning that overnight you have an extra three more hours of fasting.
Previous studies of mice and rats showed that by actually bringing their mealtimes closer together,
it actually help them lose weight and have lower levels of cholesterol and blood sugars.
So, we know it works on mice and rats, but will it work on guinea pigs?
These 16 guinea pigs were the very first human volunteers
to undergo this test in a pioneering 10-week study.
They graciously allowed the different types of fats in their bodies,
their cholesterol levels and their blood sugar levels
to be measured throughout this experiment.
So the blues got to eat their meals as normal, which meant early breakfast eating
and eating as late as they like, including a late-night snacks.
But the reds had their mealtimes restricted, which meant no late night nibbles for them.
So, Dr Jon Johnston - pretty solid name, if I may say so - ran the study.
Results are in.
Well, it’s good news for the restricted-time feeding group who ended up looking
healthier in some of our measures.
Firstly, they had lower percent body fat.
Secondly, they had lower fasting blood sugar.
And thirdly, they had lower fasting blood cholesterol.
And that is unanimous people, and it's actually very interesting
because these are major risk factors for a lot of Western diseases, such as heart disease and even diabetes.
So tell us, Jon Johnston, what's going on here?
So there are probably two possible explanations for this at the moment.
My personal favourite, because of my research interest,
is that you're eating at a time of day
when your body's metabolism rhythms are expecting you to be eating food,
so your body can deal with those calories more efficiently,
than if you eat, for example, during the night.
However, these guys have also had a longer fasting duration every day.
And it may be that the fasting in itself is having some important effects.
At the moment we just don't know,
but I think it's great that we're actually seeing some positive results.
Now, although this was just a small study, similar results have been produced elsewhere.
And basically, the fact is, when it comes to metabolism and fat burning,
your organs tend to do this when they know there's no more food coming to your body.
So if you can increase this period of fasting, mostly when we’re asleep,
you can actually burn more fats.
Now guys, try not to get too bogged down by this
and stick to some super hyper-rigid regime,
because at the end of the day, there are things that are going to get in the way.
So the major thing to take away from this is that maybe eating breakfast slightly later,
and eating dinner slightly earlier, can burn you a couple more fats.
But I'm not done yet. So if we know that changing mealtimes can make this much of a difference,
what I want to know now is, should I be eating before or after exercise?
It's not even about exercising any more.
This is about finding out whether or not we could turn our bodies into more efficient fat-burning machines.
So, brother and sister Josh and Jess were the willing lab rats this time.
So what they did was 30 minutes of exercise on an empty stomach.
Starving.
Ravenous.
Dr Adam Collins then measures how much fat their bodies burned.
What we're monitoring here is the fuels that he’s burning during exercise.
So when you're exercising, you are using a combination of glucose,
which is a carbohydrate or fat.
So what we're interested in is the impact of exercise after the exercise is finished,
because that's when you do most of your fat burning.
So most of the effect of that exercise actually happens
in the period after the exercise, rather than during it.
So then Josh and Jess get their breakfast in liquid form,
yummy,
to calculate exactly how much their calorific input is.
A week later they basically did the same thing, but this time they ate before exercise.
And the results… are a little bit weird
because the results were actually different for Josh and Jess.
So Josh actually burned 10% more fat whilst exercising on an empty stomach.
But for Jess, it was the reverse.
She actually burned more fat exercising on a full stomach.
This suggests there's actually a difference between men and women.
So to test this on a bigger scale,
we went back and teamed up with Adam Collins to get 31 volunteers to undergo a four-week experiment.
Prior to this I probably had the fitness levels of a pork scratching,
but now I feel like a much fitter, much more lively, healthier pork scratching.
And amazingly, the results were replicated.
So with the women, they actually improved by 22% more after exercising when they’d eaten.
But with the men, they actually improved 8% more by exercising before they'd eaten.
So what's going on here?
Well, it's new findings, so it's still being worked out, but it's believed that it's down
to how the different sexes handle the foods we use as fuel,
such as carbohydrates and fats.
Both men and women will store carbohydrate in muscle - and men have more muscle than women,
so they have a greater capacity to store and utilise carbohydrates.
So they're really designed to burn carbohydrate preferentially compared to women.
So basically, men are generally built to burn carbs.
So if we eat before we exercise, we're more likely to burn the carbs, than burn the fat.
So it's beneficial for us to exercise on an empty stomach,
meaning you're going to be burning more fats.
However, for the women, in general, they have more fat than men.
So exercising after they've eaten is more beneficial for them for burning fats.
So it can really make a big difference when you eat.
Equally it's important to keep a healthy perspective about this.
Yes, these are intriguing, very interesting findings
and they could be used as a general rule of thumb.
However, when the time is right for a late-night snack or late-night pizza,
you'll know.