Which Diet is Best for Gut Issues?

With constant access to social media and the internet, the advice on which diet you should follow can be overwhelming. A plethora of “experts” tell you with what seems like an absolute certainty that their diet is the healthiest choice for all.

However, should different people follow different diets? Are some of these diets even good for you at all? Which one IS the best diet for gut issues?

We will discuss the pros and cons of some of the most popular diets to give you the information you need to make an informed choice about which diet works for you.

It’s important to note that when we discuss the word “diet”, often that is associated with restriction and an aim for weight loss. The term “diet” refers to the food and drink you eat habitually and consistently1, which is the definition we will focus on here. 

The Ancestral Diet

The ancestral diet is what it says on the tin; it focuses on what our ancestors ate long ago. In the past, many diseases associated with an imbalanced gut microbiome didn’t exist. Although there are many benefits to our modern world, the health of our gut microbiome is not one of them.

Our ancestors didn’t have access to processed foods or many choices we have access to now - they ate utterly natural, whole, unprocessed and unrefined refined foods.2 This style of diet is known as eating off the land. 

Unlike many other diet styles, the ancestral diet is not known for being too strict. It is encouraged for you to follow the eating style where possible, but it is not as limiting as other diet styles.3


Cutting out processed foods is a positive thing for limiting your risk of developing diet-associated diseases such as diabetes, heart disease, and stroke.2

You are likely to eat more nutrient-dense foods whilst following the ancestral diet due to the choices of foods being mainly unrefined grains, grass-fed pastured meats, seasonal fruits and vegetables, fermented foods and wild-caught seafood.2 This makes the food choices additive and preservative-free.

The ancestral diet can help with weight loss due to the loss of access to many foods that are high in ingredients that can cause fat gain if eaten in excess. It can lower blood pressure, which reduces the risk of cardiovascular disease.3

Chronic inflammation could also be lowered due to cutting out foods like refined sugar, grains and seed oils. These foods tend to worsen inflammation, so cutting them out by following the ancestral diet can lower your risk of disease associated with inflammation.3


Restricting your food groups can lead to anxiety around eating. Seeing foods as “good” or “bad” can lead to developing disordered eating and make life much more difficult. Although this diet isn’t as strict as others, it encourages you to remove certain food groups. 

To know which ancestral diet you should follow, you must understand your traditional background. For example, you may live in the UK, but your ancestral DNA that forms some of your gut microbiomes may be from a different part of the world where food was accessed and consumed differently.

Vegan Diet 

A vegan diet is an entirely plant-based diet and lifestyle that excludes the consumption of all animal products. There can be many reasons someone adopts a vegan diet and lifestyle, including health, ethical beliefs or environmental concerns.4

For this article, we will only be discussing a vegan diet in terms of diet rather than lifestyle. 


You will likely consume far more fruit and vegetables following a vegan diet as your choices are more limited.4 This will up your intake of fibre and specific vitamins, which are beneficial for digestion and the gut microbiome. 

A vegan diet can aid in weight loss when following a health-packed diet, which limits the risk of obesity and the health issues that accompany that.4

There is significant community support for this type of diet. It can be a cult-like diet and lifestyle choice, offering help, friendship and advice within the community. For some, this can make the diet easier to stick to.  

This is such a popular diet, so many alternative options are readily available in supermarkets and shops. Meat, egg, dairy, and other tasty vegan foods are increasingly easily accessible.


Just like all restrictive diets, it can cause anxiety around eating and lead to or worsen eating disorders. When restricting your diet choices, you must be mindful that you are consuming enough food to sustain your body.

Some food alternatives for vegans can be highly processed and lack nutritional value. Often, the mindset can be that because it’s vegan, it’s healthy, but this isn’t necessarily true. Salt, fat, and sugar can often be raised to create a flavour that matches what the food is supposed to replicate. 

Iron deficiency can be common amongst those who follow a vegan diet because most iron comes from animal sources. Getting enough iron following a vegan diet is possible if you plan carefully, but taking an iron supplement is a good idea. 

Protein can also be challenging with a vegan diet, as most protein is usually from animal products like meat and eggs. Just like iron, it is possible to get enough protein with careful planning, but protein deficiency is common in vegans. 

Raw Food Diet

The raw food diet includes eating unprocessed foods that have never been heated over 40-48°C and are not refined, pasteurised or treated with pesticides. This diet can be extended to the raw vegan diet, or some choose to eat raw foods such as fish and eggs.5

The foods can be juiced, blended, dehydrated, soaked or sprouted as these methods don’t include cooking the food.5


Those that partake in the raw food diet often have an increase of raw fruit and vegetables, which ups their intake of Vitamin C, fibre and some B Vitamins. 

The raw food diet can aid in weight loss and improve vitality and energy levels. This is due to cutting out processed foods that can harm the body in regular or large quantities. There is potential for the raw diet to improve chronic diseases and overall health for the same reasons. 

The raw food diet can help control blood pressure due to the low sodium content in the foods available. This can reduce the likelihood of a stroke, heart failure, some cancers, kidney disease and type 2 diabetes.6


This is the most restrictive diet we have discussed, as it does not allow for any food substitutes and limits how you can prepare the foods you are allowed to eat. Again it is important to remember that restrictive diets can cause food anxiety and lead to eating disorders.

Cooking vegetables, in particular, is a topic for debate amongst those for and against the raw food diet. Whilst cooking vegetables kills some of the Vitamin C and B Vitamins in raw food, it also reduces certain chemicals that inhibit the body’s ability to absorb minerals such as zinc, iron, calcium and magnesium.

This suggests that eating various raw and cooked vegetables would allow you to access the nutrients vegetables offer. Still, the raw diet does not allow for this variety.

If the raw diet you follow is poorly planned, it can leave you deficient in iron, vitamin D, Calcium, iodine and zinc due to not being able to access foods rich in these vitamins or use cooking processes to bring them out. 

Keto Diet

The Keto diet, simply put, is a low-carb and high-fat diet. Reducing carbohydrates puts your body into a state called ketosis which allows your body to become very good at burning fat for energy.7 

The standard ketogenic diet follows the ratio of 70% fat, 20% protein, and only 10% carbs, although a few subcategories of the keto diet offer different ratios. Protein is limited as excess protein can be turned into glucose in the body.7


This diet is highly filling but can aid in weight loss. It can benefit those who don’t want to calorie count but want to lose weight.7 A study found that those following a ketogenic diet for 8 weeks lost almost five times as much total body fat as those following a low-fat diet.8

The keto diet can aid in diabetes. It can increase insulin sensitivity by up to 75% for some people.9 The fat loss accompanying the keto diet is another benefit of diabetes, as excess fat can be a significant factor in the development and severity of diabetes.8

More research is needed in these areas, so we implore you to take these with a pinch of salt. However, research into areas such as slowing the progression of Alzheimer's, slowing tumour growth in cancer patients, improving epilepsy symptoms in children and helping with polycystic ovaries symptoms have all shown promise.8


Limiting access to whole grains, beans, fruits and many vegetables can lead to nutrient deficiencies and cause constipation due to a lack of fibre and vitamins that aid digestion.10

A keto diet in the short term can come with uncomfortable and painful side effects known as “keto flu”. Symptoms include fatigue, headaches, brain fog and an upset stomach. Long-term risks can consist of kidney stones, osteoporosis and liver disease.10

As with every diet we have discussed, this diet again is restrictive, which can lead to disordered eating. As this diet can make you feel unwell, it may also be hard to stick to. In fact, it ranked last on the list of “Easiest Diets to Follow 2022”.11


Honestly, although all of these diets do have some benefits, restrictive eating is not something we would recommend. Limiting your choices only limits your access to vitamins, minerals and nutrients. 

You can make healthier choices without restricting yourself and risking causing an eating disorder or food anxiety. It is estimated that 1.25 million people in the UK have an eating disorder 12, which can be debilitating for those with one. 

If one of these diets appeals to you, we always recommend talking to your healthcare provider before making any changes to your diet. How about taking some of the diet styles without restricting yourself?

As the drawbacks of each diet show, not every diet is suitable for every person. Different people have different nutritional needs and limitations, and each diet can have positive and negative effects on the gut, depending on the person. 

Eating more vegan foods, fewer carbohydrates and refined sugar, less processed foods, and more raw foods may give you the health benefits you are looking for without any drawbacks. 


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