Q: When is a Calorie not a Calorie?
A: When you eat it.
This is about managing weight, and why calorie counting does not work. Delete all your calorie counting apps now…….or read on, and do it after.
Energy is produced from the carbohydrates, proteins, fats (macronutrients) and alcohol that we consume. In the science lab this energy can be measured in something called a bomb calorimeter (a fancy test tube), and is rated in terms of calories per gram. Carbohydrates and protein both come in at four calories per gram. Fat is nine calories per gram. Alcohol (obviously not a macronutrient, despite being a dietary staple of my younger years), rolls in at seven calories per gram.
The law of thermodynamics states that we lose 1lb of fat for every 3,500 calories that we eat LESS than the energy we expend. Or put another way, we gain 1lb of fat for every 3,500 calories we eat over and above the energy we expend.
The diet industry is mostly built on this principal. But it is wrong. Here are seven reasons why calorie counting may be failing you.
Reason 1. Human beings are not test tubes.
Human beings are not test tubes. Or bomb calorimeters. In a nutshell, this is why calorie counting does not work. Human beings are complex systems, not a controlled science experiment. Weight management cannot be abbreviated to calories in versus energy out.
In one highly controlled study, twelve sets of identical male twins were overfed by 1000 calories per day, six days per week for 100 days. In theory each man should have gained 24lb. In practice weight gain varied from 9lb to 29lb.
Reason 2. Your insulin response.
Insulin is a critically-important hormone involved in transporting digested macronutrients (energy) into cells. It is released when we eat food. It also increases fat and glycogen storage (glycogen is form of short-term stored energy), and prevents the body from breaking down glycogen and fat. This bit is important so I am going to repeat it. Insulin promotes fat and glycogen storage and stops fat and glycogen breakdown.
Fundamentally, insulin is brilliant stuff and you won’t last long without it. But you need the right amount of insulin, released at the right time and you don’t want it hanging around for too long. Or you may gain weight. Some foods trigger a bigger insulin response than others. 500 calories of cake releases more insulin than 500 calories of salmon. This doesn’t mean never eat cake, it just demonstrates the fact that not all calories are the same.
Reason 3. When you eat.
The same calories, eaten at a different time of day or night, can influence weight gain.
Imagine two people both consuming 2000 calories a day. Person A eats their 2000 nutritious calories over three meals, in between their meals this person only drinks water and they don’t snack. Their insulin levels will be mildly elevated three times a day and should drop off in between meals. Person B consumes a less nutritious 2000 calories, they graze throughout the day and drink regular cups of sugary tea. Person B may have a longer and higher exposure to insulin throughout the day. So, more fat storage and less fat breakdown; from exactly the same calories.
2000 calories eaten overnight promotes more fat storage than 2000 calories eaten in the day time. Our cells work to a day and night cycle, called our circadian rhythm. Eating food when our cells don’t expect it can change the way our body functions by altering gene expression. This is seen in shift workers, who are at significantly increased risk of weight gain and diabetes.
Reason 4. Gut bacteria.
It is not about calories; it is about the types of food that makes up the calories.
Amazingly, the trillions of bacteria that live in our guts can directly impact our weight. Our gut bacteria influence gene expression and affect how much energy is extracted from the foods that we eat. Having a highly diverse microbiome (lots of different species of bacteria) is a big tick in terms of overall health and appears to be a crucial aspect of successful long-term weight management. The types of foods that we eat affect the species of bacteria that inhabit our gut.
“High gut microbiome diversity and high-fibre intake are correlated with lower term weight gain in humans, independently of calorie intake and other confounders” (Menni C et al., 2017).
Reason 5. Zero or low-calorie drinks and foods.
Low calorie drinks and foods imply that you can consume them at will, and weight will not be affected. Wrong.
Low calorie drinks and foods contain artificial sweeteners. These are chemicals which taste sweet like sugar but they don’t actually contain any calories (or far fewer). But our bodies are way too clever to be tricked so easily. When we taste sweetness (even artificially induced), our bodies respond just as if we had eaten sugar. Up goes insulin (back to reason two). There is also some interesting research showing that our brains can go slightly nuts when we anticipate receiving sugar but don’t actually get it. This can have the undesirable effect of driving sugar cravings, which in turn increases the stress response associated with denial and deprivation (see reason six for why this promotes weight gain).
Artificial sweeteners have also been shown to affect our gut bacteria, encouraging growth of the less-helpful species (back to reason four).
Reason 6. Stress.
Some foods may activate our stress response more than others. Calorie counting is also stressful. And stress promotes weight gain.
Stress results in the release of cortisol (often referred to as the stress hormone). One of the side effects of cortisol is that it can make our cells resistant (“deaf”) to insulin. This means we may need to release more insulin or that the insulin will hang around for longer while it shouts louder to our now slightly deaf cells (back to reason two for why insulin promotes weight gain).
Research has shown that our brains find dieting psychologically stressful. The mere thought of monitoring food intake can set our mind off into a feeling of deprivation and panic. This means that the actual process of monitoring calorie intake may actually increase weight via the effects of our physiological response to perceived stress. If that isn’t a good enough reason to ditch the calorie counting, I don’t know what is.
Reason 7. Food is food.
Who on earth wants to think of their food in terms of calories? Food is satisfying, energising, tasty, delicious, fun, nurturing, healing, comforting, indulgent. Food is so many things, but calories? No. It really is time to move on.
Stop your calorie counting, delete your app, and tune in to your inner foodie. We all instinctively know how and what to eat; we may just have lost our way a little around food.
- Bouchard C et al., (1990) The Response to Long-Term Overfeeding in Identical Twins. The New England Journal of Medicine, 322: 1477 – 1482 (https://www.nejm.org/doi/full/10.1056/NEJM199005243222101)
- Deanna M. Arble et al., (2012) Circadian Timing of Food Intake Contributes to Weight Gain. Obesity. 17: (11) 2100 – 2102 (https://onlinelibrary.wiley.com/doi/full/10.1038/oby.2009.264)
- Menni C et al. (2017) Gut microbiome diversity and high-fibre intake are related to lower long-term weight gain. International journal of obesity 41: (7) 1099-1105 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5500185/)
- Panda S (2018) The Circadian Code. UK. Vermillion
- Suez J et al., (2014) Artificial sweeteners induce glucose intolerance by altering the gut microbiota. Nature, 514: 181 – 186
- Tomiyama AJ et al., (2010) Low calorie dieting increases cortisol. Psychosomatic medicine 72: (4) 357- 364. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2895000/)
- Tribole E & Resch E (2012) Intuitive Eating. New York. St Martin’s Griffin. 3rd,
- Woodfield J (2018) Shift work increases type 2 diabetes risk regardless of genetics. Diabetes UK. (https://www.diabetes.co.uk/news/2018/feb/shift-work-increases-type-2-diabetes-risk-regardless-of-genetics,-study-says-93985089.html)