For years we’ve been told to stick to our daily calorie count to be healthier and live longer. Foods proudly display “less than 100 calories” to virtue signal their healthfulness – but is the quest for eating less calories completely futile. Should the new paradigm of optimum health be the quality of calories not the quantity?

A calorie is a calorie right? Not exactly. 

Take this example. An avocado contains around 250 calories and a can of diet coke is less than 1 calorie. Is the healthy option the avocado or diet coke? If you were to make the decision based on the much-loved concept “eat less calories”, then logically you would choose diet coke over the avocado. Nutritionally speaking, this isn’t the good option. Let me explain why. It is well-known that diet coke contains harmful artificial sweeteners that trigger sugar cravings as they’re up to 100 times sweeter than normal cane sugar, so your taste buds become desensitised to the taste of normal sweetness found in nature. This sets you off on the sugar rollercoaster, your insulin levels go haywire and your sugar cravings get worse – the “Diet Coke addiction” is a very real phenomenon. That single calorie comes at a cost to your health!

Comparatively, avocados, in moderation, contain a variety of beneficial nutrients including good fats, antioxidants and vitamins, cause minimal insulin response and ultimately this is the healthier choice every time. I’ve heard many people say that they avoid avocados because they are high in calories. A well-known slimming club in the UK ranks an avocado on the same nutritional level as 2 curly wurly chocolate bars (apparently frozen bars are best, as they take longer to eat). The basis of this decision is solely down to calorie content BUT ignores the insulin release and hormonal impact of sugar in the chocolate bar. It is this kind of simplistic approach to food and nutrition that confuses people. 

Listen up guacamole lovers – avocados will not cause weight gain, curly wurlys will, whether they’re frozen or not.

Why the calorie deficit equation is an illusion

IF CALORIES EATEN ARE LESS THAN CALORIES USED = CALORIE DEFICIT = WEIGHT LOSS

This is the alluring weight loss formula that many health experts, dieticians and personal trainers base their health plans on. Essentially, when we eat MORE calories than we burn, the excess calories will be stored as fat. When we eat LESS calories than we burn, the weight will fall off – this is known as a calorie deficit. 

Sorry to break this to you but this is NOT the mechanism that causes our bodies to store fat. This myth has been pedalled by dietary associations including the BDA (British Dietetic Association) for decades and probably explains the catastrophic failure in combatting the obesity epidemic. The very foundation of our understanding of weight management needs to be turned on its head to reverse this tide.

Our bodies do not have an in-built calorie calculator totalling up the calories in and calories out. Real world studies confirm the abject failure of this stunning calorie counting fiasco. Weight management by calorie counting has an estimated 99.4% failure rate – yes 99.4% – this is not a typo. The calorie theory of weight loss should be consigned to the nutritional science rubbish heap.

What exactly is a calorie?

The amount of energy in an item of food or drink is measured in calories. The calorie count is calculated by burning foods and applying an out-of-date mathematical calculation to account for different rates of digestion and absorption. No doubt, you can easily calculate the number of calories in a particular food but what is less certain is how different people’s metabolism respond to those calories. 

A calorie is a unit of energy just like a cm is a set unit, but it does not maintain its rigid value once it enters the body due to the complexities of food metabolism in the human body – this is unique to each of us. A good example is almonds – these tasty nuts have had their calorie count inflated by 30% for decades and it has been found that the absorption of the fat is variable; therefore, calorie calculations vary greatly from one person to the next. How the body produces energy from food varies enormously depending on the state of the food, how you chew it, how easy it is to digest and what you combine the food with. It is abundantly clear that the personalised, biochemical response is the missing piece of the calorie jigsaw. 

WHO guidelines recommend that adult males require 2,500 calories per day and females 2,000. Again, this is very much an “average” and doesn’t take into account the fact that the basal metabolic rate (this is how much energy your body needs for basic functions) can vary by 40%, physical activity levels, fitness and muscle mass. The brain requires huge amounts of energy to function.

Furthermore, the formulas behind food labels are over 100 years old and outdated. Food manufacturers are permitted a 20% error rate on their food labels. In fact, research has shown that calories on food labels can underestimate calorie count by 70% (!) this is not merely a margin of error, it is wholly inaccurate. The key message here is that the calorie count on food labelling cannot be trusted and shouldn’t be the main guiding factor for making healthy food choices. 

Instead, we should be guided by our Grandma’s wisdom when it comes to the food on our plates – eat more natural, seasonal wholefoods and less ultra-processed foods. Everything in moderation. And most importantly reclaim mealtimes as joyful experiences and not laden with guilt and calorie counting.

The insulin theory of weight loss

Body weight and body fat are not consciously regulated but involve the complex interplay of various bodily systems – thyroid, parathyroid, sympathetic, parasympathetic, circulatory, respiratory, gastrointestinal and adrenals. Hunger is controlled by hormones – ghrelin causes hunger and cholecystokinin signals fullness. You are not overweight because you lack willpower or motivation, these hormones exert a powerful effect on your instinctive hunger signlas. What’s worse is that weight loss leads to higher levels of ghrelin, making us hungry and hence the challenges of trying to sustain traditional low-fat, low-calorie diets. What does work is a more balanced diet with nutrient-dense foods – fresh vegetables, more fibre, good fats and more protein; this helps with satiety – the satisfaction and sense of fullness after eating.

Interestingly, fat storage is driven by genetic, diet, environment and lifestyle factors and the complex interplay of hormones, especially insulin (the hormone that controls blood sugar levels and body fat storage). 

A quick summary on insulin is helpful at this point. When we eat carbohydrate foods, they metabolise into glucose for fuel – some glucose is used by the body immediately for energy and some will be stored for future use. Carbohydrates cause blood glucose levels to rise beyond the desired range. The hormone insulin is secreted from the pancreas to help push the glucose from the bloodstream and into the cells and this process helps to bring the blood sugar levels back into range. Insulin also regulates how much glucose will be used immediately and how much of the excess glucose will be stored as glycogen in the muscles and liver (for later use). If the glycogen is not used in 24 hours, then the excess will be stored as fat, and weight is gained. This is the hormonal theory of obesity and in my opinion, should become the new paradigm of weight management.

Why calorie counting doesn’t work?

I’m sure we know all the feelings that come with starting a new diet. You are pumped with motivation, your mind becomes fixated on the food you can and cannot eat, you mentally beat yourself up about being good or bad on a given day and the diet seems to take over your life. Our relationship with food is a very primitive one and has become riddled with complexity in modern times. There is an evolutionary mismatch between our primitive eating habits and the food culture we find ourselves in – we used to eat for survival and now our hunger instincts are overridden by other complex signals in the modern food environment. 

When you dig deeper into calorie restricted diets, the success of those who have lost weight, can be attributed to the nutritional quality and quantity of the food consumed rather than merely reducing their calorie intake. On a so-called calorie-controlled diet, the actual quality of food will generally improve and contain more nutrient-dense foods such as salads and vegetables and less ultra-processed foods, less alcohol and more physical activity. Indirectly, insulin levels will be better managed on this regime – but the false veil of “eating less calories” is used to explain its success. The calorie myth should be dispelled as it drives people to make dysfunctional food choices and harms public health. 

In recent years, nutritional science is proving that we respond to different foods in a unique way – you will digest, absorb and utilise the energy from food differently to others. Fascinating twin studies have shown that how we use energy and the extent to which we store fat and gain weight is largely dependant on our genes. For example, some people have genes that will extract more energy from carbohydrate foods, causing a greater insulin spike and increased likelihood of fat storage. Interestingly, food metabolism will also vary according to the length of an individual’s length of intestine (part of the gastrointestinal tract). The gut microbiome also has an important role to play. Cutting edge research on the different varieties of bacteria in your gut shows that there were up to 400% variations of energy response to carbohydrate foods (2015 study, 800 participants). Gut bacteria such as Akkermansia muciniphila and bifidobacterium were shown to be at higher levels for those who maintained a healthy weight. It is useful to note that the gut microbiome changes according to diet and lifestyle.

3 reasons to stop calorie counting:

1. Focus on carbohydrates for weight management

Low calorie diets usually allow more carbohydrates to be eaten as the calorie theory states that carbohydrates contain 4 calories per gram – protein contains 4 calories per gram and fats contain 9 calories per gram. This ignores the insulin spike and fat storage potential that comes with eating carbs, especially refined carbs.

Your body does not gain weight because you are eating too many calories – your body systems will respond to the chemical composition of those calories. Get your energy from vegetables, fruits, good fats, protein and some complex carbs. Most people need to reduce refined sugar and carbohydrates in their diet to a maximum of 130g per day if they want to lose weight for the long-term.

2. Try intermittent fasting instead

When you reduce your calorie intake by up to 40%, your metabolism will slow down to conserve the limited energy you have, so you will not burn excess fat unless you severely restrict your food intake beyond this 40% threshold. This is why intermittent fasting is so effective as it gives your body a chance to deplete its glucose stores and burn fat for fuel rather than glucose, hence aiding weight loss.

3. Diet and lifestyle change go hand in hand

It is more important that we understand our individual eating behaviours and take a holistic approach to wellbeing that includes nutritious food, moving more, better sleep and mindfulness. Evolution means that body fat is one of the most important biological determinants of survival in the wild, so think yourself lucky if you store more of it (!) sadly today there is an evolutionary mismatch and many of us are storing excess fat. We are eating for many reasons beyond survival and the nature of food itself has altered dramatically. It is time for a health revolution – ditch calorie counting and eat joyfully again.

References

1. NHS – https://www.nhs.uk/live-well/healthy-weight/why-we-need-to-eat-carbs/
2. https://www.diabetes.org.uk/
3. https://www.lowcarbprogram.com/
4. https://invivohealthcare.com/
5. https://www.bda.uk.com/
6. Spector, T. (2015) “The Diet Myth”. 1^st edn. London: Weidenfeld & Nicolson.
7. Spector, T. (2020) “Spoon-Fed”. 1^st edn. London: Penguin, Random House.
8. Guyenet, S. (2017) “The Hungry Brain”. 1^st edn. London: Penguin Random House.
9. Dr Fung, J. (2018) “The Diabetes Code”. 1^st edn. Canada: Greystone Books. 
10. Bazzano L, Reynold K, Yao L et al. (2014) Effects of low carbohydrate and low fat diets: a randomized trial [online]. Annals of internal medicine. 161(5), 309‐318

11. Luckni, S. Khan, C. Lakkunarajah, S et al. (2017) A systematic review of evidence on the use of very low calorie diets in people with diabetes [online]. Current Diabetes Review. 13 (1), 35-46. DOI: 10.2174/1573399812666151005123431