Only until relatively recently in human evolution have we eaten three meals plus snacks every day. Breakfast simply didn’t exist for large parts of history. The Romans, for example, didn’t eat it – usually consuming only one meal around midday – breakfast was actively frowned upon. Regular working hours following the industrial revolution brought structure to mealtimes to sustain labourers. And by the late 18th century the pattern of eating three meals a day in towns and cities emerged.

Erratic eating patterns

But these days, people are eating more frequently than they ever have before – and often outside of meal times. New smartphone app data shows that we now have erratic eating patterns. Many of us are continually snacking rather than eating at defined times – which means we spend up to 16 hours a day in a “fed” state.. So, the gut is also a dynamic barrier between us and ‘them’.  How exactly it lets food though and keep the bugs out is marshalled by the tight junction proteins.  These acts as the doormen between the epithelial cells which line the GI tract.  Most of the time, the tight junctions are kept tight, separating the gut contents from the rest of the body.   But each time we eat, the gut barrier must become transiently permeable, known as ‘leaky gut’.  This permits the absorption of essential fluids and nutrients from a meal but comes with a collateral challenge – silent inflammation.

Inflammation

While inflammation is a normal response of the body to infection and injury, which provides protection against stressors. This means that just the act of eating imparts a degree of physiological stress on the immune system: For around four hours after eating our gut microbes and their components leak into our bloodstream – silently triggering inflammation by the immune system.   Even the ‘good’ bacteria in our gut can become problematic if they escape their home in our gut and enter the bloodstream.  This is known as post-prandial endotoxemia.  Sounds very sinister, but this short-lived phenomenon is physiologically normal. It can be exacerbated by calorie dense meals, excessive fructose and fatty foods (particularly saturated fat) and is counteracted by a diet rich in fibre and plant polyphenols found in fruits and vegetables.

While leaky gut is a symptom not a cause, type ‘leaky gut’ into Google and you will quickly get the impression that it’s a catch-all cause for long list of ailments.  But post-eating leaky gut isn’t a cause for concern in healthy adults eating at defined mealtimes.  Inflammation is only ever meant to be a short-term protective assault by our immune system. But inflammation after eating can be exacerbated by our modern lifestyles. This includes calorie dense meals, frequent eating, excessive fructose and fatty foods – particularly saturated fat.

We still don’t know the cumulative impact on disease risk of healthy adults who spend longer periods of time in a post-fed inflammatory state. But what is clear, is that low-grade inflammation is the most important driver of unhealthy ageing. Persistent postprandial inflammation is a problem because it inflicts recurrent collateral damage on our body that is extremely detrimental to our health over time. Chronic low-grade inflammation has emerged as an important link to many non-infectious lifestyle-related diseases including heart disease and type 2 diabetes.  Reduced frequency of eating through intermittent fasting or time-restricted eating also highlights the broadly beneficial effects that eating less has on human health. This includes aiding weight loss and lowering the risk of metabolic diseases, such as diabetes. On the basis of available data, the fact that such a fundamental aspect of our dietary habits – the number of meals we eat every day – has not yet been subject to rigorous scientific investigation is remarkable.

But what we do know is that not only does snacking increase your likelihood of elevated inflammatory markers, but eating excessive calories also leads to weight gain. Eating late has also been linked to elevated cholesterol and glucose and can make you more insulin resistant. This leave you feeling hungrier the following day. So, it might be worth consolidating your food into fewer, more satisfying meals. You might also want to reduce your eating window to ten hours day or less and aim to eat your last meal earlier in the day – your body will thank you for it.