Sugar: The Body’s Response And The Gut Microbiome Episode 3 – The Pleasure Trap


Sneaky Peek

For us, as a family, changing our eating habits to better support our gut microbes is as much about knowing what gets in the way as it is about knowing the positive steps we can take. This piece is about what gets in the way. Our evolutionary urge for pleasure – for a burst of dopamine. Calorie-dense food elicits a dopamine hit in our brain which FEELS GOOD. This had a purpose when we were hunter-gatherers. It motivated us to travel far and wide in search of really nutritious calorie-dense food. We don’t have to travel far any more. We don’t have to travel at all. And food producers know we want that dopamine hit. They design food with that in mind. Unfortunately, it tends to be calorie dense but not nutritious. Read on for more detail.


We think we are evolved but really, we are mostly a cluster of ancient instincts and microbes. Acting on our subconscious urges a lot the time. I am not sure that listening to some of these urges, certainly in terms of food, is a healthy way to navigate modern life. It probably increased our chances of survival when we were hunter-gatherers but it appears to be doing the opposite now.

Most of us want to be healthy. For those of us that don’t care, it is likely that things have already gone wrong for us, probably on many levels. Mostly though, health is our aim because, when we are healthy, we are not constrained in how we can live our lives by pain, discomfort, fear, medication, side-effects and so on.

It goes without saying that many, many people suffer illness for reasons beyond their control. Here, I am talking about illness or lack of health that occurs through choices we make for ourselves. This is terribly complicated, I accept, because some of the choices we make don’t really feel like choices because we have been programmed by our genes to some extent, by our environment from as far back as the womb and by the microbes we have in our gut. And we don’t feel we have control over any of that.

In this final episode of the sugar trilogy, I want to look at what gets in the way of making better food choices; of continuing to make better food choices. If we can start to see the puppet strings, we might just be able to cut them and thereby regain some control. I want to look at the dietary pleasure trap (so named by Alan Goldhamer) (1).


The Dietary Pleasure Trap

Evolutionarily, humans aim to maximise pleasure, minimise pain and achieve those two goals in the most efficient way possible. As we have evolved, the ways in which we achieve pleasure have become more and more complex but the fundamental ancient drivers are still alive and kicking.

The most basic human drive is survival. Survival can be summed up in just two words – eating and reproducing. These activities enable us to pass on our genes. I am going to focus on the eating side of things.

Dopamine is a neurotransmitter, a pleasure brain chemical. Our brain rewards survival behaviours with a dopamine hit. Interestingly, dopamine is also one of the neurotransmitters that our gut microbes are involved in producing. It is important in the gut as well as in the brain.

The higher the calorific density of a food, the greater the dopamine hit we receive when we consume it. In fact, just looking at these foods can activate the relevant parts of our brain.

As hunter-gatherers, this adaptation worked to keep us seeking out food that was calorie dense. This made sense when survival depended upon good choices between the cost in energy terms of finding/catching such food and the reward in terms of the energy density of the food obtained. The more energy rich the food, the more dopamine flooded the brain. It makes less sense now though, when calorie-dense food is ubiquitous.

We are no longer hunter gatherers. In fact, we live in a world where food producers design food with that perfect combination of fat, sugar and salt so as to activate our dopamine centres deliberately. This food is available all of the time and we need expend very little energy in order to obtain it. We are now in a situation where the ancient evolutionary drive for the dopamine hit is still powering our food choices but the evolutionary reason for this drive is now redundant. Previously, it motivated energy expenditure to find calorie dense food for survival. It has become the opposite of a survival mechanism in the 21st century.

We remain motivated to get the dopamine flowing but artificial, highly palatable foods that make our dopamine sensors go wild also tend to have many times the number of calories that healthy naturally-occurring foods contain. And barely any of the nutrients.

Not only is this type of food desirable to us because of the dopamine release it gives us, it also upsets the balance of our fullness and hunger hormones so that we desire it even when our body isn’t biologically in need of it – this is hedonic hunger (a term coined by the clinical psychologist Michael Lowe (2)). When was the last time you just couldn’t stop eating chocolate/cake/biscuits/doughnuts/crisps (delete as appropriate). When did this last happen to you with, say, apples? You finished one and another was just calling to you from the fruit bowl?

In addition, consumption of highly processed foods also negatively affects the diversity of our gut microbial population. These foods are mainly absorbed in the small intestine, which starves our gut microbes (mainly inhabiting the large intestine, which is the final furlong of gut before the anus.) This situation is not beneficial to gut health, immune health, in fact any sort of health.

Minimising our intake of the foods that mess with our fullness and hunger mechanisms enables us to cut the dopamine puppet strings. Our brain is not set up to cope well with a constant supply of processed foods. It has built-in mechanisms designed to regulate our intake of natural foods but processed foods trick it and keep us eating to get the dopamine hit we then become so dependent upon.

In one American study, after a diet of unlimited junk food, the pleasure centres of some rats’ brains became desensitised to dopamine after only 5 days (3).  This meant they required yet more of the same to elicit a pleasure response (4). When the junk food supply stopped, the now obese rats preferred to starve themselves for two weeks rather than eating their standard rat chow food. (5)


changing our food environment

The thing is, simple will-power is often not enough to break this cycle. Some experts (like Michael Lowe) suggest that we need to change our own food environments. I know this to be true from my own experience! By changing our own food environments, he means not putting this stuff on our shopping lists, not buying it when we are shopping, not bringing it into our homes – limiting our exposure to temptation where possible. This evolutionary urge is challenging to resist. The truth is though, the less of it we eat, over time, the less we crave it, not just because our hunger and satiety hormones will become less disordered but also because this type of food upsets our gut microbiome so avoiding it helps to reset that too. Read my post on Gut Microbes and Appetite.

Now that we are aware of the puppet strings, we can start to think about our behaviours around food in this context. Whilst I am not pretending for one minute that this is easy, the reassuring fact is that we can wean ourselves off our processed food/dopamine cycle by firstly, knowing it exists and secondly, adjusting our food environment as much as possible to avoid those foods high in sugar/fat/salt/calories but low in nourishment.

Conveniently, it is these same foods that also reduce microbial diversity and increase gut microbial dysbiosis, which are equally problematic situations for us. Limiting these foods as much as possible will benefit us in both departments!

As usual though, it is no good just focussing on what to cut out (or cut right down). We also need to increase our intake of a diverse range of nutrient-dense whole foods. Why? Because these foods do not upset our fullness and hunger hormonal system. They don’t mess with our heads. They are packed with nutrients, good fats, fibre – all the things our bodies need to function well. And they help support gut microbial diversity. This all sounds preferable to me than the food I eat effectively yanking me about like a puppet on a string.

Wondergut Wisdom

Remember this is more complicated than simple self control. There are many forces at work that influence our behaviour around food.

The first step, for us, has been simply beginning to see this in action.

The next step has been acknowledging that better supporting good eating practices starts with what we actually buy. That is the first port of call for observing and resisiting our urges!


  1. The Pleasure Trap: Alan Goldhamer and Douglas Lisle
  2. Hedonic Hunger: A new dimension of appetite: Michael Lowe and Meghan Butryn Physiology & Behavior 91 (2007) 432 – 439
  3. Dopamine D2 receptors in addiction-like reward dysfunction and compulsive eating in obese rats: Johnson, P.M. Nat Neurosci May 2010; 13(5) 635-641
  4. Animal models of sugar and fat bingeing: relationship to food addiction and increased bodyweight: Avena, N.M., Methods Mol Biol (2012); 829: 351-65.
  5. The obesity epidemic: the role of addiction: Taylor, V.H., CMAJ (9 March 2010); 182(4): 327-8.


Spreading straightforward information about the fundamental importance of a healthy gut microbiome.