Inner Sense: How the New Science of Interoception Can Transform Your Health (published by Profile Books/Hachette India) looks at the intersection of many sciences to understand how humans can improve their health. It does not necessarily focus on those identified as clinically sick for whatever reason. Even able bodied individuals have their moments of anxiety, self-doubt, and possible physical manifestations thereof. It is about knowing oneself better without advocating positive toxicity. Caroline Williams attempts to understand scientifically the underlying reasons for a diverse group of individuals feeling the way they do. Her sample cases are fairly varied. She also advocates trusting one’s gut, following one’s instincts and trusting one’s heart.

On p.78 she makes a valid observation:

The brain’s predictions and interpretations of what’s happening in the body can carry a lot of weight in the equation that adds up to how we feel. So it stands to reason that if we could somehow change what the brain thinks is happening in the body, it mught help to change how energised we feel.

An important aside: I’m not suggesting that anyone with chronic fatigue is able to think themselves better. Research suggests that this condition is usually the result of a physical glitch in the system, not an imagined one, and the same is true of many instances of everyday fatigue.

Later she discusses at length about the importance of gut health and recognising the signals.

p.101ff …gut feelings are so important. If hunger didn’t make us feel bad and eating didn’t feel good, our prehistoric ancestors might have wasted away in a cave rather than risk going out hunting and gathering. If being sick didn’t feel so miserable, we might not learn to avoid bad food, and the next rotten piece of meat could kill us. And if we didn’t know to stop eating when we felt full, we might keep seeking out food at the expense of other important things, such as staying safe and warm and fostering life-enriching relationships.

These relationships are as important for our survival as finding enough calories. Humans are relatively puny compared to our natural predators, and we have long childhoods, during which we are dependent on others for food. It makes sense that at some point in our evolution, the basic motivational feelings for finding food were recycled as motivators that prompted us to seek out social institutions. As a result, we get hungry for food but also for human connection and comfort. We feel sick not just when we’ve eaten something rancid but also when a creepy stranger stands too close to us. And we feel warm and fuzzy inside when eating our favourite meal and when we’re with someone we love. For most of our evolutionary history this system has guided us well. But in a world where comfort food is easier to come by than meaningful human connection and where much of what we eat is tastier than it is filling, it can be a struggle to know what our bodies — and minds — are asking for.

To make things even more complicated, food and comfort aren’t the only things our guts communicate with the brain about. The gut is hardwired into the fight-of-light system, meaning that it also sends out signals that are a side effect of a body-wide call to action. We all know what it feels like when our stomach flips when we are nervous; when we are faced with a life-or-death situation (or a more trivial social encounter that feels like one), digesting our last meal can wait. The blood that would usually be required for digestion is diverted to the muscles and brain, so its share of glucose and oxygen can be used to deal with the emergency. The sensation of a knot deep in your stomach, the fluttering of butterflies or a cold wave as the blood drains from your belly is a direct result of digestion grinding to a halt while the blood is sent elsewhere.

This system also works well — at least, when we need a burst of energy to deal with a cahllenge — but it can easily get out of whack in the stressful modern world. The link between emotional issues and digestive problems that has long proven difficult to explain is becoming increasingly clear — and even harder to treat in a medical system that thinks of conditions as being either physical or ‘all in the mind’.

All things considered, the overlap between our gut feelings and emotional state means taht trusting your gut is not always as straightforward as it might be.

p.111ff It is often said that the gut has a ‘second brain’ that operates semi-independently from the brain in our heads. The enteric nervous system is embedded in the gut walls along most of the gut, and contains more neurons than the spinal cord. It’s reputation as a second brain comes from the fact that it can manage the complex process of digestion without any input from the actual brain, regulating the contractions that push food through the gut and the hormones involved in the digestion.

While the enteric nervous sytem can do a lot without the say-so of the brain, they are not totally disconnected. Over the past decade, it has become clear that the insides of the gut not only talk among themselves via the enteric nervous system, but are also in constant contact with the brain, via the vagus and spinal sensory nerves. These lightning-fast connections mean that the brain hears what’s happening in the gut in miliseconds. It also means that whatever is happening in the brain affects the gut just as quickly. This is the much-talked-about gut-brain acix, which is proving to be a new frontier in understanding what makes us tick — and what makes us sick.

This is a fascinating book. It goes into a fair amount of biochemical details about how these systems are interconnected inside us. Also, sharing new scientific discoveries or rather finding scientific evidence for statements (as mentioned above) that people have made for a long time and discovering the truth.

Perhaps this book is for you, if you are an eclectic reader, perhaps it is for you, if you are a specialist interested, but it is definitely for you if you are charmed by Ozempic and Wegovy.

27 July 2025