Myths about Calories

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Just another dirty little secret

In the pre-challenge information I spoke about the way in which calories are determined. It involves a lab, burning the food in question and measuring the temperature rise in a specific volume of water. This has no bearing on how our body metabolises or breaks down food and certainly will have no bearing on how your body stores fat. Before we go any further, I’ll explain to you a bit about food metabolism. It’s not as simple we like to think it is and is vastly different from person to person.


Your body obtains energy through 3 sources; fats, carbohydrates and protein. These are collectively known as macronutrients (as is water) whilst micronutrients are vitamins and minerals. In terms of energy availability of the macronutrients they are as follows:

1 gram of protein yields 17kJ of energy (~ 4 calories)

1 gram of fat yields 37kJ of energy (~ 9 calories)

1 gram of carbohydrate yields 16kJ of energy (~ 4 calories)

1 gram of fat yields 37kJ of energy (~ 9 calories)

1 gram of carbohydrate yields 16kJ of energy (~ 4 calories)

1 gram of protein yields 17kJ of energy (~ 4 calories)

So as we can see fat has the highest yield of energy per gram (hence the low fat message for weight loss). It dies however cost the body more energy to extract energy from dietary fat than it does from dietary carbohydrate and recent studies have shown us that the net energy availability from fat is actually closer to 5 calories. Fat and protein metabolism is quite complex and the amount of energy available for metabolism is limited as fat and protein are also needed in many cellular processes and structures. In this way, they are essential for human function as they are used in so many roles throughout the physical body. Carbohydrate metabolism is a little simpler than fat and protein metabolism as carbohydrate is mostly used either for immediate or future energy requirements. So whilst scientists are able to make good estimates on the macronutrient content of food reasonably, they are guessing, at best, as to the caloric availability of these macronutrients during digestion.

When we take a look at a label on a food, we should consider a few things but how many calories are in the food is not one of them. Things to consider are:

1. Sugar content (particularly fructose content)

2. Fats and oils

3. Carbohydrate content

Quite simply, if it is a packaged food, we should be eating limited amounts of it and if it’s a chocolate bar (for example), common sense tells us that it is loaded with energy and we need to eat a very small amount of it and very infrequently. Calories on food labels are guesses at best and so the numbers on food labels are so inaccurate that they make the labels meaningless.

The amount of energy we obtain from our food also comes down to:

- Our levels of stored energy (i.e. if we’re low on stored carbohydrate, we will utilise and store a complete lot from our next meal. Conversely if we’re at maximal carb storage already then what we can’t use immediately will get stored as fat)

- Our moods (i.e. stress decreases nutrition absorption from food due to high levels of adrenaline)

- Our hormone control (hormones direct us to store energy and/or use energy)

- How we prepare our food (cooked, raw,diced, chopped etc.)

And more! Food metabolism is not a simple process so why do we keep trying to make it so?

So why calorie labels then? Well you’ve all heard of calorie counting, yes? Calorie counting is a recent phenomenon that was designed to assist in weight management. First you calculate metabolism using a basal metabolic rate (BMR) equation which then gives you an idea of how many calories you can consume in a day. To be fair, it was a reasonably logical idea as it was known that over eating leads to becoming overweight, but research is showing us that what is in the food is far more important than the calories in the food. This is because not only are calories in food an estimate but so are BMR calculations. We don’t know on a day to day basis exactly what our BMR is as not every day is identical. Doesn’t it make more sense to eat for the needs of each day? Each day our energy needs vary and different people also have different energy needs. This is because many things influence our metabolism such as:

- Genetics

- Sleep

- Smoking

- Medications

- Stress

- Menopause

- Dieting history (particularly calorie restrictive dieting)

- Lean tissue

If you see a diet that tells you to eat a certain number of calories every day (i.e. the ridiculous 1200 calorie diets for women) RUN for the hills! Those types of diets are dangerous, set you up for failure and completely show a lack of understanding of the human body. As an example, Kate and Nary decide to take up the 1200 calorie diet. Mary is 150kg and eats 3000 calories a day . She has a BMR of 2200 calories. Kate is 80kg and eats 2000 calories a day. She has a BMR of 1650 calories. Both of these girls are drastically different yet neither one of them should take on 1200 calories as suggested by this diet. For both of them, it is a very low calorie diet (VLCD) and it will lead to the body thinking it is starving and slowing down to try and save itself. It will also lead to hunger and cravings by both girls. They may stick to this for a while but ultimately they will cave in and go back to their normal style of eating and gain back their weight (and then some, due to a loss of muscle tissue). The sad reality is that this is what leads to the vicious cycle of weight gain and weight loss most women fall victim to.

I’m sure many of you have, at some point been told (rather condescendingly too I might add), that weight loss is simply a matter of moving more and eating less! It does make sense if you don’t think about it for too long or do any substantial research. If you do, look to the extensive research, you will see that this is not the full case. The ‘calories in versus calories out’ does not produce the long term results that people are after. Why is this? Well there are a number of reasons but I’ll start with the most straight forward.

1. The ‘calorie in/calorie out diet’ is ultimately a VLCD diet particularly when combined with exercise. As I’ve already discussed these do not produce long term results and can have very significant and adverse long term effects on metabolism (via the catabolism of muscle tissue).

2. To see significant body fat reduction, a program needs to be adhered to over a long period of time. Adding to this, at the completion of the program, the participant can’t revert back to their old styles of eating and drinking as they will gain back the weight again. Due to these types of diets relying strongly on will power, most people eventually cave in.

The first two points are relatively straight forward but the third involves some explanation of our messenger systems.

1. Our body responds to stimuli via two systems. The nervous system and the endocrine (hormonal) system. When they are working together they can be collaboratively called the neuroendocrine system. The neuroendocrine system is vital in appetite regulation. If it is disrupted (from disease, genetic influences, environment, diet and/or lifestyle) it can create appetite problems leading to either over or under eating. Both are problematic but in modern society, the biggest and most common appetite problem is over-eating. So what can disrupt this operational system, from a dietary perspective? Well many things but refined carbohydrates mostly, particularly sugar! When there is an overabundance of sugar this leads to an increase in fatty acid formation and a disruption in our hormone signalling. This can mean you never feel full and will overeat. Think about this for just a minute. Your previous failures of diets are not necessarily because you were undisciplined and lazy. It could be because the underlying issue of your overeating was not addressed. This is crucial information! Hormones play many many roles, but from a dieting perspective they tell us when we’re full, when we’re hungry, when to store energy as fat or glycogen, when to use energy and where to store fat. If this system becomes unbalanced (for whatever reason) all of the above functions may not be working properly and efficiently.

So what should you do about this? I suggest before anyone attempts a lifestyle change and/or diet they need to get to the doctor to get their blood checked. I would suggest a:

1. Fasting blood glucose test

2. Fasting blood lipid profile (ask for an oxidised LDL test)

3. Cortisol check

4. Discuss with your doctor the need for testosterone, progesterone and/or oestrogen checks

These tests will give you a clearer picture of what is happening inside your body and aid in the success of the program. At the final end of the day, following this challenge will have positive effects on numbers 1-3 but number 4 will need to be discussed further with your GP.

The best news of all is this; when we stop consuming large quantities of fructose and allow our in-built appetite control centre to do its job, our body regulates our hunger and we tend to not overeat naturally. So the upshot of it all is: stop counting calories but also STOP eating the foods that have calorie labels on them!!