A common explanation as to why we gain or lose weight involves phrases such as: 'energy in vs. energy out', 'move more eat less' or 'calories consumed vs. calories burnt.' But what are we really talking about, and how much of this is under our control?

WHERE DOES OUR ENERGY COME FROM?

Energy is derived from the foods we eat. This energy is either stored or used to fuel activity right away. Our stored energy and our food, are used together to fuel everything we do each day. 


WHERE DOES OUR ENERGY GO?

Much of our energy is spent on activity beyond our control such as:

INVOLUNTARY NEAT (Non-Exercise Activity Thermogenesis: Spontaneous movement such as fidgeting)

BMR (Basal Metabolic Rate: Energy for cellular activity and sustaining life)

TEF (Thermogenic Effect of Food: Energy for digesting food) 

EnergyBalanceDanPRice

SO WHAT DO WE CONTROL?

The rest of the energy we expend is very much under our control. Cycling to work, taking the stairs, getting up from our desk, walking the dog or tracking 10,000 steps a day. These are all ways we can consciously increase our activity, and use more energy (Voluntary NEAT). Excluding exercise, the variance between two people’s calorie expenditure in one day can be as much as 2000kcal! (1) (think: postman vs. office worker!)


The amount of energy we take in is also under our control through the food choices we make each day. If we regularly take in more energy than we use up, over the course of days, weeks, months and years our weight will slowly increase as more and more energy is stored. If we are regularly consuming less energy than we are expending, then over time our weight will decreased as we use up our body’s stored energy.


WHY DOES WEIGHT MANAGEMENT BECOME DIFFICULT?

While the processes of energy balance sound simple, our bodies are very clever, they have evolved over thousands of years to make us really good at storing energy - and more and more efficient with how we spend it! This was great for surviving long famines in millennia gone by, but less helpful in today’s society; where food is both abundant and ingeniously designed to be even more calorific than foods readily found in nature (AKA Doughnuts). Chronic weight gain over time can also make the situation more difficult, as the body becomes resistant to hormones controlling hunger and satiety. (2)

In the same way,  crash diets and fads often fail because extreme calorie restriction can lead to serve hormone responses that can make adherence almost impossible - this is often the cause of the “yo-yo effect’ of extreme dieting. A sustainable approach to weight loss, involves incremental and sensible changes to your food choices and activity levels.


SUSTAINABLE APPROACH?

See my Practical Weight Loss Advice article for strategies to implement sustainable changes to your diet, that can help realign your energy balance and bring about weight loss without the Yo-Yo effect.
 


References:

(1) https://www.ncbi.nlm.nih.gov/books/NBK279077/ (2014) von Loeffelholz, C
(2) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2967652/ (2010) Martin G Myers Jnr, et al