Intense mental activity, calorie burning and fat / weight loss

Can you lose fat and cellulite just by studying hard?

Recently, I had a conversation with a client who had read somewhere that the brain consumes about 20% of the body's daily energy intake. The client in question is a PhD student and does indeed use her brain a lot, studying for several hours a day, and insists that studying hard is what keeps her weight down.

Given that she hates exercise and loves sweets this seems to be a very convenient and attractive theory for her, as if true it would allow her to avoid exercise, eat whatever she likes and then burn the extra calories by studying hard - and gaining a PhD in the process!

However, this theory is not backed up by any evidence, except perhaps this specific clients' apparent slimness. On the other hand, the cellulite on her legs (the reason for which she came to see me in the first place) indicate that there is a serious fault with her theory.

So, given that lot of women seem to be confused about this matter, I will try to elucidate the connections between brain activity, fat loss and cellulite, and put the myth to rest once and for all.


Brain energy consumption - as compared to muscle, fat tissue and heart energy consumption

The fact is that the brain does consume 22% of our daily caloric intake, which is a substantial amount of energy, equivalent to about 400 calories per day (assuming that a typical woman consumes about 1,800 calories per day). This is exactly the amount of energy consumed by all the muscles of the entire body on a normal day when exercise is not performed (22%) and also practically the same to the energy consumption of the liver, the body’s chemical powerhouse (21%).

This is to be compared to the energy consumption of the the heart (9%), kidneys (8%) and fat tissue (4%). And yes, fat tissue does burn some fat, although normally it does not burn enough fat to lead to it’s own demise - although scientists are working on that (for more info on this exciting field of science please check the "beige fat" tag on the sidebar on this website).

The brain is indeed an energy-hungry organ. Scientists propose that the brain's lust for calories drove us to seek energy-dense diets based on meat (in addition to vegetarian food), as opposed to the strict vegetarian diet of our ancestors, which did not provide enough energy and building blocks for the brain. Conversely, some paleoanthropologists claim, the availability of energy-dense animal food has led to the increase in brain size and the development of modern human, Homo Sapiens Sapiens.

In any case, although the brain does consume a whole lot of energy, not all of this energy is used for conscious thinking. A lot of it is used to regulate the various systems of the body and keep the existing knowledge intact, in much the same way a computer continually uses battery power to keep RAM-memory data intact and prevent their loss.

Therefore, an increase in mental activity (i.e. studying) by 50% will not translate to 50% more brain energy consumption, i.e. this extra mental effort will not make our brain burn 600 calories per day instead of 400 calories. The difference is more likely to be +10% or +20% brain energy consumption (nobody knows the exact amount), i.e. a more modest +40~80 calories per day. In contrast, a 30’-minute running session will lead to the oxidation (burning) of an extra 200-300 calories, depending on the individual.


Intense thinking and metabolism

On the other hand, intense thinking will almost definitely lead to increased noradrenaline/dopamine release and consequent nervous alertness/tension, which will in turn increase the overall whole-body metabolism and the "burning" of even more calories.

At the moment no studies exist to quantify the effect of intense thinking on the overall increase of metabolic rate, so this information can only be speculative, but the truth is that people who think a lot (or worry a lot!) tend to generally be slimmer than people who don't need to think very hard or laid back people who ...“take it easy”.

Of course, a whole lot of other factors are involved in staying slim/getting fat, including diet, exercise, general daily physical activity and genetic predisposition, but generally speaking, intense thinking most probably helps us stay a bit thinner.

However, calorie burning in the brain, and the consequent increased metabolic rate, do not lead to the increased muscle mass that exercise offers (muscle consumes a high amount of energy, even when at rest), neither it improves aerobic capacity or overall health - although it obviously does improve mental ability.


Intense mental effort and cellulite

Of course, intense thinking does not protect from cellulite, even though it may lead to a moderate decrease in fat accumulation, a major component of cellulite.

This is because when we think intensely, i.e. when studying or working in front of the computer for hours on end, we tend to sit on our bums, thereby minimising circulation and mechanical stimulation in the areas most prone to developing cellulite: the buttocks and the back of the thighs.

Poor circulation leads to water retention (an important aspect of cellulite), while lack of mechanical stimulation leads to lack of skin firmness and overall skin tissue weakness / flabbiness (another important cause of cellulite). Therefore, we can safely conclude that studying or other intense mental work does increase cellulite even though it most probably moderately boosts energy consumption.

In fact, this conclusion agrees to loads of anecdotal evidence, which shows that women with sedentary occupations that involve hard thinking (i.e. researchers, students, traders, bankers etc.) may sometimes be slim, but almost always suffer from loose skin and cellulite...


One more thing...

Oh, and there is one more thing. To work mentally very intensely for hours on end, most people, especially women, feel the need to consume some form of sugar or other refined carb, such as chocolate. This is because the brain uses glucose for energy and needs a steady level of blood sugar maintained at all times.

A high level of blood sugar is a bit better for intense mental work, offering the so-called "sugar rush", but not very good for the rest of the body, both in terms of health and also weight gain / cellulite (excess blood sugar becomes fat if not used immediately and to maintain the sugar rush you need more sugar than the rest of the body is comfortable with).


As a practical note...

If you do have to be stuck in front of your computer for hours on end, do not expect your hard brain's work to keep your skin in good shape, even if you don’t snack on sweets and other “brain candy”.

Instead, try to undo the damage that sitting on your bum causes to... your bum, by taking frequent short breaks for walking and by doing at least 30’ of exercise a day (power plate is the best for this specific purpose), daily applying a quality anti-cellulite cream and, if you can afford it, try to regularly receive a good cellulite treatment that will provide some much needed stimulation to your skin's collagen cells on the areas of bum and thighs.