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A note before we start. This episode discusses calorie counting and food restriction. So if this doesn't feel right for you, please skip to the next episode. You're lying in bed, stomach rumbling. Nope, can't take this anymore. You rush to the kitchen and scramble through the cupboards, checking the backs of each packet and cereal bar. Surely I can eat something else today. And there it is, the glorious 35 calorie cracker you needed.
You savor every bite because tonight you've reached your limit. 2,100 calories. Tick. Another day of calorie counting down. Sigh. While counting calories might seem to make sense, you may be surprised by the latest science. This is Zoe Science and Nutrition. I'm Jonathan Wolf. And today on the show, we find out whether calorie counting is good for your waistline or a waste of time.
This episode is part of a limited series to celebrate the launch of the Big If Study, the world's biggest clinical study to discover how intermittent fasting really affects us. By inviting our amazing community of citizen scientists to take part in this experiment, we hope to understand whether intermittent fasting really can improve how we feel.
from our hunger levels to our mood and energy. To take part for free and discover if intermittent fasting can work for you, simply go to joinzoe.com/thebigif, that's T-H-E-B-I-G-I-F, or by the link in the show notes. The countdown is on, one day until you can join. We've brought top nutritional scientist, Sarah Berry, in on this one because she gets food,
She's spent more than 20 years figuring out how food interacts with our bodies. I've done lots of work around the area of bioaccessibility, which is looking at how much of a nutrient and energy within a food is actually available for us. So let's start at the beginning. What exactly is a calorie? A calorie is a simple measure that we use in order to quantify how much energy is in food.
One calorie, or strictly speaking kilocalorie, is the amount of energy needed to raise the temperature of one liter of water by one degree centigrade. And that energy is what keeps our bodies functioning. We burn calories every day just by existing, and even more if we're active.
So on the surface, calorie counting makes a lot of sense. Say your body burns 2000 calories a day and you only eat 1500. You're going to lose weight, right? There's a belief that if we can carefully control how much energy we're consuming in calories and also control how much energy we're using, i.e. through physical activity or other means, that we will be able to control our body weight. But
But actually, it's a lot more complicated than that. Not as simple as it sounds then. You see, we're not actually that good at measuring calories. And when food enters our bodies, calories aren't all equal.
If we use nuts as an example, when we consume nuts, we actually excrete about 30 to 40% of the energy, so 30 to 40% of the calories in nuts. And this is because of the structure of the cell walls. And so the calorie count that's on the back-of-pack labeling of nuts versus the calorie count that we actually use, we actually metabolize, is out by anything between 30 to 40%. And that's just one example.
The way we measure calories is so inaccurate you could even be eating more than you think. But what if you really are eating fewer calories than you're burning? The truth is, you will almost certainly see the weight drop off. Calorie counting is good for short-term weight loss. But as with all good things, it doesn't last.
If you do what we call yo-yo dieting, which often happens where people might calorie count because they've got a wedding to go to, the evidence shows that you tend to not maintain that weight loss and you tend to actually, for many people, increase the weight above what was your original weight in the first place.
The reason that people rebound is that when you reduce your calorie intake, what happens is signals go to your brain telling you you're even more hungry and trying to drive you to consume even more calories than you've actually stopped consuming. You can't fight your body's natural instincts. Evolution has designed them to be difficult to ignore.
And those hunger cravings are often made worse because calorie counters may not focus on what is in the food they eat. Reaching for low-fat and low-sugar foods with fewer calories on the label to help them stay within their calorie allowance for the day, rather than picking foods with high-quality ingredients. Often it's done through the consumption of low-sugar or low-fat foods that we know are packed full of very highly processed and other unfavourable and unhealthy ingredients.
From upsetting the balance of our gut microbiome to causing spikes in our blood sugar levels, heavily processed foods not only make us feel hungrier, they come with some pretty nasty long-term health consequences too. So, best case calorie counting scenario, you lose a little weight, then you struggle to lose any more. Worst case, you feel hungrier, your diet quality slips affecting your health, and you end up weighing more than when you started.
So what should you do? My recommendation is that people think less about the calories and more about the types of foods that they're consuming. And by changing to healthier foods, more plant-based foods, fiber-rich foods, diverse diet is likely to improve your health from the inside.
which over the long term is likely to improve your weight. And it's likely to improve your weight in a more stable way that you can maintain rather than the rapid weight loss that you might see with calorie counting that is very difficult to maintain. So you've listened to this whole episode, but if you're still intent on counting your calories, I can't blame you. We've been conditioned to think of food like this.
So if you just can't stop counting, make sure they're quality calories. Sarah says you should try thinking about fast and slow calorie foods. Fast calorie foods are these ultra processed foods, heavily refined foods. They're very quickly absorbed. They're rapidly metabolized. You have these big sugar peaks and dips, which cause you to be actually more hungry more quickly.
Now, you could have the same amount of calories in another food, but this might be within a more slow food. So foods that are minimally processed and foods that look like the original food item that they actually came from. And this will cause a more blunted rise in blood sugar. You won't get the same dip and you won't feel as hungry later. So there you have it. Calorie counting can work, but when it does, it's not for long.
Food quality plays a much more important role in long-term health and sustained weight management. So for all of the back-of-the-packet reading part-time mathematicians out there, it might be time to put the pen and notepad down and restock your cupboards with some healthier and tastier choices. Maybe try our intermittent fasting study instead. I mean, who wants to be counting calories for the rest of their lives anyway?
The episode you just heard is part of a limited series to celebrate the launch of The Big If Study, the world's biggest clinical study to discover how intermittent fasting affects our mood, energy, and hunger. To take part for free and discover if intermittent fasting can work for you, simply go to joinzoe.com slash thebigif or via the link in the show notes.
This episode was produced by Fascinate Productions with support from Yellow Hewings Martin and Alex Jones at Zoe. Zoe Daly's come out each day between now and our next regular episode.
