Why counting calories rarely has the desired long term effect
Posted on 28th July 2021 at 07:35
Calories – and calorie counting – have been the mainstay of weight loss regimes for many years, regardless of how they’re packaged or marketed. Or which celebrity is endorsing them (!).
The logic is quite simple. We all know it by heart, it goes like this:
Excess calories = weight gain.
Therefore fewer calories = weight loss.
Which naturally leads on to the “more is better” approach. Or, more accurately, “less is better” one (!).
In other words, the more controlled and restricted the diet is, the fewer calories are consumed and the greater – and quicker – the weight loss. Well, in theory (!). Which means we can then go back to eating the foods we really want to.
And, sadly, this is how most people still view weight loss diets. A short term solution to a “problem”, rather than a long term one focussed on maintaining steady weight and good health.
Unfortunately, as all too many dieters will testify, this approach never seems to give the desired results. Quick and easy weight loss in the short term. Sustained weight loss over the long term.
Even worse, it often leads to so called “yoyo dieting”. Weight is lost – hurrah (!) – but then, just as quickly, put back on. And, usually, in much greater amounts. Then, just to rub salt into the wound, it gets progressively harder to lose any weight at all. And so a depressing downward spiral begins.
Why is this?
Well, sadly, there are several major flaws in this approach to losing weight which tend to be overlooked or ignored. And we’re going to look at a couple today.
The first one is very simple. Not all calories are the same. And, if this sounds like a strange thing to say, bear with us. It’ll all make sense in a minute. Yes, it will!
In simple terms, a calorie is a unit of energy. Historically, it was used to show the amount of heat produced by different energy sources, such as wood, coal or gas. However, it was quickly realised that it could also be used to measure the energy produced by different types of food. Whether generally from fats, proteins, carbohydrates or sugars OR specifically from individual foods such as chicken, carrots or bread.
This led to the easy assumption that whatever energy was produced by a particular food in laboratory conditions was what was made available to the body as energy. For example, if one particular food produced 100 calories in the laboratory, then it also made 100 calories available to the body.
However, this misses out on a very important part of the equation. The energy used by the body to break down and process the particular food, to make the 100 calories available. Hopefully, you can see where this is going (!) but, to be on the safe side, we’ll continue with an example.
Say the food was difficult to digest, requiring 50 calories of energy for the 100 calories to be made available. This would mean that the net effect of eating the food would be 50 calories. Hurrah (!).
By contrast, if the food was very easy to digest, requiring only 10 calories of energy to be expended to release the 100 calories, then the net effect would be 90 calories. This is why basing a diet purely on the number of calories being consumed is so problematic.
Looking at food groups generally, there are no prizes for guessing which foods fall into which category. Protein takes longer to break down and digest, so expending more energy in the process, as do fruits and vegetables high in fibre. At the other end are carbohydrates and fruits with high sugar levels, which are quickly digested, so expending much less energy in the process. This leaves healthy fats in the middle, although much nearer to proteins. It’s also why meals – or snacks – high in protein and / or healthy fats keep us feeling “full” for much longer than those high in carbohydrates or sugars.
And, as an aside, there are also no prizes for guessing where processed and ultra processed foods fit into this. While these are marketed as being equivalent to home cooked foods, they are bulked out with higher levels of carbohydrates / sugars and unhealthy fats. Then, just to make matters worse, the production process reduces the amount of fibre they contain; making them quick and easy for the body to digest with all too predictable results. And that’s without any of the nutritional issues associated with processed foods…
Which leads us on to the other major flaw in the calorie controlled approach we’d like to highlight today. This is that it doesn’t take into account the nutritional content of food, treating all foods as the same nutritionally speaking.
However, this is clearly not the case. It doesn’t automatically follow that a high calorie food also provides high levels of nutrition; any more than a low calorie food provides low levels of nutrition. It’s another reason why being on a diet of any sort doesn’t automatically guarantee good nutrition levels. The food we eat is not solely about energy, it’s about nutrition too. And, to our bodies, nutrition is just as important as the energy a food provides.
This has led to the popularity of low GI diets to try and address the problems of the calorie controlled approach. GI stands for “Glycaemic Index” and measures the amount blood sugar levels rise, two hours after eating a particular food. In other words, it shows how quickly a food is broken down – or how easy it is to digest – and how much blood sugar levels then rise as a result.
The GI figure given to any food is between 0 and 100; with 0 meaning there’s no increase in blood sugar levels, while 100 is the increase in blood sugar after consuming a pure glucose drink. So, the logic is easy to see. To base the diet around foods with low GI figures which, in practice, means non starchy / sugary vegetables and fruit along with lean proteins and healthy fats. Which, in turn, ensures the diet is based around whole foods, so addressing the nutrition issue at the same time. Hurrah!
And, again, there are no prizes for guessing the foods best avoided. All the high carb / sugar / unhealthy fat / processed foods along with starchy / high sugar vegetables and fruit such as potatoes, carrots and dried fruits.
Sadly, once again, there’s another flaw in this logic which tends to be overlooked in the process. It’s GL or “Glycaemic Load”. GL goes one step beyond GI and provides a much more meaningful picture of the effect a particular food has on the body. While GI measures the increase in blood sugar, GL focuses on how quickly this increase occurs. In other words, how quickly blood sugar rises after eating a particular food.
Again, there are no surprises that the high carb / sugar / unhealthy fats / processed foods which everyone loves so much all have a high GI AND high GL. They lead to a substantial rise in blood sugar AND this occurs very quickly after they’re eaten; as they’re so quick and easy to digest. Which takes us straight back to processed and ultra processed foods…
Similarly, lean meat such as chicken, has a low GI – as it doesn’t contain carbohydrates – AND low GL as it has little effect on blood sugar levels.
However, there are anomalies, with watermelon being a very good example – and illustrating why GI on its own can be very misleading. With a high GI figure of 70, watermelon would seem to be high in sugar and so best avoided. But, from a GL standpoint, its high water and fibre content means the sugar is only released very slowly AND at low levels, so it doesn’t cause a rapid rise in blood sugar. As a result, it has a low GL figure and, as an aside, makes a great alternative to the other fruit juices we love so much.
There’s so much more we could say on this topic but, to keep this blog post to a manageable length, we’re going to stop there for today. We trust we’ve given you plenty to think about and, once again, shown why simple long term changes are always going to win the day. Short term, quick fixes are rarely that, proving once again that our bodies are so much more intelligent than we could ever give them credit for.
As always, the choice is yours.
Photograph by unknown author
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