There is a commonly held myth that reducing carbohydrates promotes weight loss and it is indeed a very convincing argument. We have all tried a low-carb diet at least once in our life and the chances are that it worked. Think about it, reducing processed, calorie dense carbohydrates and replacing them with protein and whole, unrefined foods will drastically reduce your calories and therefore your waistline. Furthermore, research has shown that eating more protein, as well as fibre, keeps you fuller for longer so you will subsequently lose weight. It isn’t cutting carbs alone that makes us lose fat.
Carbohydrates raise the hormone insulin in our bodies and there is a misconception that this hormone makes us hungry and prevents us from burning fat choosing to store it instead. It goes something like this:
1. We eat carbs
2. Insulin is released
3. It makes us more hungry
4. We store fat
It is important to note, however, that whilst carbohydrates do cause insulin to spike, this is a natural process that occurs to regulate hunger not increase it. Insulin is in fact an appetite suppressant and a very powerful one at that. Whilst it does cause blood sugar to rise, this doesn’t continue all throughout the day. It only takes place in response to a meal. Here is how it actually works (image from James Krieger):
Whilst insulin is high, your body does tend to burn carbohydrates over fat (highlighted in green) but once it has reduced again fat is burned (demonstrated in blue). So, as you can see, it all balances out over the course of 24 hours. Furthermore, evidence has demonstrated that protein can have just as much an impact on insulin release as carbohydrates do so purely demonising carbohydrates is ludicrous!
Are Low Carb Diets Actually Superior?
There has been a plethora of research in to this area in recent years and they all draw the same conclusion; low carb diets do work in the short-term but they are no more effective than any other form of calorie restriction.
One study showed the same amount of weight loss in participants when they followed a high carb diet proceeded by a low carb version. 1.1lb was lost in both scenarios despite the fact that the low carb diet saw insulin reduce by half. This effectively disproves the insulin hypothesis as have many other studies that I have referenced in other blogs.
As I discuss here, weight loss doesn’t magically occur just by restricting a certain food group – it all comes down to calories in vs calories out. When you are eating less than you burn, you will lose fat with or without carbohydrates in your diet.
Do Carbs Make You Gain Weight?
It is clear that you do not need to restrict your carbohydrate intake to lose weight but what about the notion that carbohydrates make you fat?
This idea stems from the fact that when we eat carbohydrates, we prioritise burning these over fats. However, this is a transient process and once complete, our bodies go back to burning fats as pictured in the diagram above. It is all part of homeostasis; our body’s way of regulating itself so that it all balances out at the end of the day.
Contrary to some claims, it is very rare that carbohydrate is ever ‘turned in to fat’. This can occur but only when carbohydrates are over eaten on a HUGE scale. One study showed this to happen when 1000 grams of carbohydrates were eaten in a day – to put this in to context, the average UK female eats less than 200 g a day when not on a low carb diet so would have to eat at least 5 times as much! Not very comfortable….
Fundamentally, numerous studies have shown that when calories are like for like, the same amount of weight is gained when fats or carbs are over consumed.
They have further demonstrated that carbohydrates do not influence body weight any more than fats do when a person is not overeating and therefore in energy balance.
When calories are matched, there appears to be no ‘best’ way to prevent weight gain or promote weight loss. It ultimately comes down to the amount you eat not what you eat and this should be driven by personal preference.
With that said, processed, greatly refined carbohydrates should not make up the majority of your diet. If you do choose to retain carbs in your diet, choose whole, unprocessed versions whenever possible. High carb junk foods are lacking essential nutrients, don’t fill us up and ultimately lead to us overeating. This excess of calories is what is at the root of the obesity epidemic, not carbohydrates as such.
However, if you find that a low carb approach is the best way to keep your calories low and maintain your health then go ahead. Just be aware that it is not the only approach but it may well be the best one for you as it helps you to stay on track.
But if it is a struggle and you love your carbs, then there is no reason not to eat them as long as your calories are in the right place.
This was brought to you by Rebecca Flannery, Evidence Based Nutritionist