In one of the professional Facebook groups I’m part of questions about clients looking to lose weight very often come up. And always a slurry of responses come in that say ‘the client is under-reporting because you cannot beat thermodynamics – calories in must be less than calories out to lose weight’.

Where to start…

I think the first point to make is that the calculation of calories is extremely flawed. As this article states:

‘To accurately calculate the total calories that someone gets out of a given food, you would have to take into account a dizzying array of factors, including whether that food has evolved to survive digestion; how boiling, baking, microwaving or flambéing a food changes its structure and chemistry; how much energy the body expends to break down different kinds of food; and the extent to which the billions of bacteria in the gut aid human digestion and, conversely, steal some calories for themselves.’

Consider the foods like corn and seeds that can pass through our digestive systems unchanged. We can only be getting so many calories from something we cannot breakdown.

And this paper which analysed data in the US from 1974-2006 and in 164 countries from 2001-2010 says:

‘However, the reported caloric content of a food is not necessarily equal to the energy absorbed by the body; for example, the energy contained in insoluble fiber is subtracted from total caloric content because it is understood to provide no physiological energy. ‘

and

In contrast to assumptions underlying the static calories in, calories out framework typically implemented in models of utility maximization, different nutrients of equal caloric content could have varying contemporaneous and dynamic effects on weight.

Basically, using calories reported on the back of a packet is not all that useful for calculating the calories you are absorbing.

The same study reports that weight gain was most strongly associated with an increase in carbohydrates, while an increase in fat intake actually decreased obesity prevalence. This is why more people these days are focusing on macros (amounts of protein, carbohydrates and fat consumed daily) rather than calories.

The type of carbohydrate is also important. There is some research suggesting fructose is more likely to lead to weight gain for example and the glycemic index of a food changes how quickly the carbohydrates are broken down and then released into the blood. The faster they are broken down, the more likely the glucose will be converted to fat storage UNLESS you’re about to start exercising, in the middle of a long session or just finished. Then that glucose is very useful.

What else?

Well, the number of hours we sleep can have a profound effect on our weight.

Studies consistently show that shortened sleep increases snacking, the number of meals eaten per day, and the preference for energy-dense foods.

The association between sleep duration and macronutrient intake suggests that longer habitual sleep duration could ameliorate the genetic predisposition to obesity via a favorable dietary profile.

It’s a bit of a vicious cycle: the less we sleep, the more energy we need or cravings we get and therefore the worse our food choices are, which then impact our ability to get to sleep later. But it’s not just that – some people are genetically predisposed to obesity depending on the number of hours they sleep. Sleep is also where some of our best healing, learning and growth occurs so it’s wise to get into good habits with it.

Anything else to consider?

Well your hormone profile (and therefore your age and gender) will play a huge role. This book I’m currently reading, Roar:How to Match Your Food and Fitness to Your Unique Female Physiology for Optimum Performance, Great Health, and a Strong, Lean Body for Life, goes into detail about it. Women in particular will experience differences in weight simply because they go through high and low hormone phases every month. During the high hormone phase, weight gain will often occur simply due to extra water retention – nothing to do with calorie intake.

The book also explains that women need very different diets during and after menopause. A shift to higher fat, lower carb diet is recommended and women should focus on the right proteins to ensure optimum lean mass development with correct timing and type.

(FYI: Women should have higher percents of fat in their body, 12-30%, whereas men can be healthy with as low as 5% body fat and up to 25% so be mindful of this if you are looking to get extra lean. Fat is essential to us all.)

The hormones that dominate women’s body composition are progesterone and estrogen but there are many others involved in weight control in both genders too, namely ghrelin, glucocorticoids (in particular, cortisol), insulin, and leptin. One paper discusses that hormonal changes in the body encourage a person who has lost weight to put it all back on again and these hormonal changes actually persist for at least a year. The participants lost 10% or more of their initial bodyweight over 8-10 weeks and then kept the majority of the weight off for the year by following a diet and exercise regime but still at the end of the year their body was resisting this new weight and trying to get them to eat more and store more energy rather than burn it. This can help explain why it is very difficult for those who have lost weight to keep it off.

This paper ‘suggests that various lifestyle factors can help attenuate the hormonal responses normally associated with appetite control and regulation. Specifically, eating more frequent and smaller meals comprised of moderate protein levels and lower fat, obtaining normal sleep of 8 hours a day, and controlling stressors and levels of psychological stress could more readily control the levels of “appetite hormones.” Additionally, it is recommended that exercise, both endurance and resistance training, should be incorporated into any lifestyle or behavior enhancement program. In closing, development of a weight loss program requires an integrative approach of many professionals including physicians, psychologists, nutritionists, and exercise physiologists who can as a team propose an optimal personalized strategy taking into account all aspects of obesity.’

Bit more complicated than a calorie-in, calorie-out approach eh?

Lastly, I’d like to touch on what was mentioned early on, the gut microbiome. This is only just starting to be heavily investigated and recognised as being crucial to understanding digestion and optimal nutrition. We all have have distinctly different communities of gut bacteria living in us which means we all digest and assimilate food and energy differently (hence the rise in trend of ‘gluten sensitivity’). In the linked article, a study is described between mice injected with the microbiome of an obese twin versus their leaner twin.

The mice ate the same diet in equal amounts, yet the animals that received bacteria from an obese twin grew heavier and had more body fat than mice with microbes from a thin twin.’

The gut is so complex and basically a world of its own that it has it has its own [enteric] nervous system and is considered our ‘second brain’. I look forward to seeing where the research takes us in the future into understanding what benefits we can get from understanding our own personal microbiomes!

In summary, if you’re trying to lose weight through diet (and you have a low stress life with a good sleep cycle) I advise you to respect the fact that you are not in total control of your metabolism. Respect what your body needs; lots of vitamins and minerals, the right balance of protein, carbs and fat, plenty of water and daily exercise. If you tick those boxes without going overboard, your body will assume its healthiest shape and size. My best simple tips would echo what Girls Gone Strongadvise; drink more water, keep your main meals full of real ingredients, eat protein with every meal (especially at breakfast) and don’t eat so much you feel like you’re bursting out of your jeans!

As ever, if you have any questions, simply send me an e-mail or comment below!