Why Your Gut Matters for Weight Loss: Part 3

When Your Gut Is Trying to Tell You Something

I ask almost every patient in clinic about their gut health and whether they have any issues.  The answer I often get is, “It's fine.” Then we start talking. They are bloated most evenings, only open their bowels two or three times a week, regularly take something for indigestion, belch after meals or have so much wind that they have simply learnt which trousers not to wear after dinner. In other words, their digestion is not fine. They have simply lived with these symptoms for so long that they have become their normal.

This is something I would really like us to change. Bloating, reflux, constipation and excessive wind are incredibly common, but common does not necessarily mean optimal. Nor does every digestive symptom mean there is something seriously wrong. Our digestive systems are allowed the occasional grumble, particularly after a large meal, a change in routine or a weekend when we have eaten rather differently from usual. It is persistent or recurring symptoms that interest me, because they can provide useful clues about how well the digestive system is actually working.

Think back to our factory and conveyor belt that we discussed in our previous features. Food needs to travel through the digestive system at the right speed, spending enough time at each station for stomach acid, digestive enzymes, bile and bacteria to do their jobs. If that conveyor belt slows down, things begin to back up. Food stays in parts of the digestive tract longer, fermentation can increase, gas can build up, and bowel movements become less frequent. If things are not moving efficiently further down, we can also start noticing problems further up, including fullness, belching and sometimes reflux.

This is why I don't like looking at digestive symptoms in isolation. Someone might think their reflux is a stomach problem; their bloating is caused by something they ate and their constipation is simply because they need more fibre. Sometimes that may be true, but when those symptoms regularly appear together, I start looking at the whole digestive process. What is slowing the conveyor belt? Is food being broken down properly? Is the person eating enough? Are they drinking enough? What is their microbiome doing? Have they recently taken antibiotics? Are they under enormous stress? Are medications affecting motility? There are often several pieces to the puzzle.

Bloating

Bloating is a good example because it is so often blamed on simply having “too much gas”. In reality, bloating is more complicated than that. It can be associated with constipation, altered gut motility, food intolerances, changes within the microbiome and increased sensitivity within the gut itself. This explains why two people can eat exactly the same meal, and one happily carries on with their afternoon while the other has undone the top button of their jeans by three o'clock.

Wind can give us another clue. Producing gas is completely normal. Our gut bacteria ferment parts of our food, particularly certain fibres and carbohydrates, and gas is one of the natural byproducts. A healthy gut is not a silent gut. The problem is when gas becomes excessive, painful or noticeably different from your usual pattern. That can suggest that food is being fermented differently, that transit has slowed, or that particular foods are reaching bacteria in quantities they are struggling to handle.

Constipation

I am less interested in whether someone manages to open their bowels at precisely the same time every day than in whether their bowel movements are regular, comfortable, and feel complete. If someone is straining, passing hard stools, regularly going several days without a bowel movement or constantly feeling that they have not emptied properly, I want to know why. Slow transit changes the environment inside the bowel and commonly coexists with bloating, excessive fermentation, and changes in the microbiome. It also affects how someone feels. If your abdomen is distended, your clothes feel tighter, and the scales have suddenly crept upwards, even when some of that change simply reflects what is sitting within the digestive tract and associated fluid shifts rather than an increase in body fat, it can be incredibly disheartening. For someone already struggling with their weight, that alone can be enough to create the feeling that nothing is working and derail their motivation.

There is another important reason we need to keep things moving. The bowel is one of the body's routes of elimination, including compounds that have been processed by the liver and passed into the gut through bile. Oestrogen is a good example. Once the liver has processed oestrogen, some of it passes into the gut ready for elimination, but our gut bacteria can influence whether some of those oestrogen metabolites leave the body or are recycled back into circulation. It is one of the reasons I pay attention to bowel function and the microbiome when looking at the wider hormone picture, particularly around perimenopause and menopause. It is certainly not as simple as saying constipation causes hormone imbalance, but good bowel function and a healthy microbiome are important parts of the body's normal clearance and recycling systems.

Often to deal with constipation, we ramp up our fibre intake and for some people this works, but for others, it can feel like things have got worse.  Let me explain why “eat more fibre” does not work for everyone. Fibre is incredibly important for gut and metabolic health, and in a healthy gut it helps nourish many of the beneficial bacteria we want to encourage. But if the digestive conveyor belt is already moving too slowly, or there is an overgrowth or excessive fermentation taking place, adding lots more fermentable fibre can sometimes be like piling more boxes onto an already struggling production line. Instead of solving the problem, we may provide even more fuel for fermentation, leaving someone more bloated, windy, uncomfortable and constipated than they were before. 

This does not mean fibre is bad, far from it. I often compare it to exercise. Exercise is one of the best things we can do for our bodies, but you would not go for a five mile run with a broken leg and expect it to make the leg better. You repair the injury first, then gradually return to exercise. I look at fibre in much the same way. If the gut is struggling, we may sometimes need to address what is going wrong, improve motility and calm excessive fermentation before gradually building up the types and amounts of fibre that help the gut thrive.  We will come back to this in the next part of the series because fibre deserves a proper conversation of its own.

Reflux

Reflux deserves attention too. We often assume that reflux automatically means too much stomach acid, but the reality is more complicated. The movement of food through the stomach, meal size, pressure within the abdomen and the function of the valve between the stomach and oesophagus can all play a part. This is why repeatedly suppressing the symptom without considering what may be contributing to it does not always answer the bigger question. Persistent reflux, particularly if it is new or worsening, should, of course, be discussed with your healthcare professional rather than simply self-treating indefinitely. 

All of this becomes particularly relevant for anyone using GLP 1 based weight loss medication. These medicines affect digestive motility and can slow gastric emptying, particularly earlier in treatment. This can contribute to feeling fuller for longer, but digestive symptoms, including nausea, constipation, uncomfortable fullness, and reflux, can occur. This can help people feel fuller for longer, but digestive symptoms, including nausea, constipation, uncomfortable fullness, and reflux, can occur. For many people, these are manageable and improve as the body adjusts, particularly when treatment starts at a low dose and increases gradually, but they should not simply be ignored. If the digestive conveyor belt was already struggling before treatment, slowing parts of it further may make an existing problem much more noticeable.

This is something I feel particularly strongly about because I regularly see people who had digestive symptoms before starting weight loss medication. Perhaps they were already constipated, bloated after meals or regularly experiencing reflux, but they had simply accepted those symptoms as normal. Slow the digestive conveyor belt further and suddenly a problem that had been quietly rumbling away becomes much harder to ignore. This does not mean the medication is unsuitable or that everyone taking it will experience digestive problems. It means supporting gut function should be part of the conversation, rather than waiting until someone becomes so constipated or uncomfortable that they are desperate for help.

If eating leaves you bloated and uncomfortable, you naturally begin changing what you eat. People start removing foods, often without really understanding which food is causing the problem or whether food is actually the main problem at all. Vegetables disappear because they cause bloating. Fibre is reduced because it produces wind. Protein portions shrink because someone feels uncomfortably full. Before long, the diet becomes smaller and smaller, and someone who is already eating less because of weight loss medication may also be eating a much narrower range of foods.

This is something I find incredibly frustrating in clinic. So many patients have lived with digestive symptoms for years because they have been told their tests are normal, there is nothing seriously wrong, or they have been given a diagnosis such as IBS and come away believing this is simply something they have to live with. It is important to understand that conventional medical investigations are primarily designed to rule out disease and significant pathology, and that is absolutely vital. But being told there is no evidence of disease is not quite the same as saying your digestive system is functioning brilliantly. There is a lot of space between serious disease and optimal gut health, and that is often where my patients are sitting.

So perhaps the message from this article is a very simple one: listen to your gut. Bloating, reflux, constipation and excessive wind are common, but that does not mean you should automatically accept them as your normal. Sometimes they are the smaller clues that help us understand how well your digestive system is actually working, and addressing them can make an enormous difference, not only to how comfortable you feel, but to how well the whole system functions.

In the next article in this series, we are going to tackle one of the most confusing subjects in gut health: fibre. We all know fibre is supposed to be good for us, but what happens when eating more of it actually makes you feel worse? We will look at which fibres feed your microbiome, how fibre may support natural GLP-1 production, and why the answer is not always to add more.