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Can gut health affect your weight?

/ Health & Fitness

One of the common questions I am asked by people is how to lose weight. For many people this is simple eat less and move more which indeed is a big part of it, but many people have found this isn’t the whole story. It may seem odd to many of us why digestion has anything to do with weight but a growing body of research thinks not.

Gut health has received a great deal of attention lately and those who’ve been on my workshops will know I often say “you are what you eat, digest and absorb”. Meaning you can eat all the right things but if you have issues with digestion and/or absorption then this could mean you don’t fully benefit from your healthier diet. Gut bacteria have a big part to play in digestion and absorption, in fact some researchers have deemed that gut bacteria are so important all health and wellbeing stems from them.

In this blog I want to draw your attention to the subject of gut bacteria and how it could impact on weight management. You may at first wonder how something microscopic could impact your weight, well let’s look at some recent findings.

Prof Spector from King’s college has been researching gut health for many years and asks the question ‘are bacteria in our gut making us fat?’. He also believes gut bacteria have amazing power over our health, including our mood.

Prof Spector suggests that “if you put identical twins on high-calorie diets, where they eat an extra 1000 calories every day, after six weeks they’ll have completely different changes in weight. Some will have gained as much as 13Kg, others as little as 4Kg, all on 100% identical diets”. Interestingly there was also a notable difference in their gut bacteria. The leaner twin had more varied and healthier bacteria, and the fatter twin had a less diverse profile including some bacteria associated with inflammatory conditions.

So when trying to lose weight would focusing on gut bacteria be a great approach to go alongside exercise?

Research indicates that gut microbes are not only essential in digesting food but they also control how many calories we absorb. The less diverse our gut microbes are the more likely we seem to be affected by metabolic conditions like diabetes.

One interesting study followed a 22 year old (physically fit) whereby he would spend 10 days eating only McDonald’s meals! His initial gut bacteria levels were monitored to give a baseline. After 6 days, the individual reported feeling bloated and sluggish. On the eighth day, he’d started to sweat after the meals and his friends remarked that his skin seemed to have a yellow tinge and he looked unwell. By day 10, the individual had gained four pounds and 1,300 bacterial species in his gut had been totally wiped out!

One of the most interesting findings was the bacteria left in his gut had changed in nature. Bacteria that are associated with inflammation had increased sharply and those that create chemicals to fuel our cells had been slashed. Interestingly the individuals gut bacteria started to return to normal after going back to his usual diet.

With this in mind you may say great so how do I actually go about getting good bacteria in to my gut?

Dr Micheal Mosley and his research team allocated people in to three groups and over four weeks asked each group to try a different approach that, its claimed can boost gut bacteria. The first group tried an off the shelf probiotic drink of the type found in most supermarkets. The second group tried a traditional fermented drink called Kefir which contains an array of bacteria and yeast. The third group was asked to eat foods rich in a prebiotic fibre called inulin. Prebiotics are substances that feed the good bacteria already living in our guts, and inulin can be found in chicory root, Jerusalem artichokes, onions, garlic and leeks.

The biggest change was in the kefir group. These individuals saw a rise in a family of bacteria called lactobacillus, well known for their impact on gut health.

To summarise:

  • Changing from a processed diet to more healthy eating can improve your gut bacteria.
  • Including foods such as onions, garlic, leeks, chicory root and Jerusalem artichokes in your diet can improve gut bacteria.
  • Consuming fermented foods such as Kefir appear to have a very positive impact on your gut bacteria.
  • It also appears that if you want to try fermented foods to improve your gut health its best to look for products that have been made using traditional preparation and processing or make them yourself, to ensure you’re getting the healthy bacteria.
  • Having the right balance of good bacteria appears to have a strong link to improved digestion, absorption and hence weight management.

For further advice on any of these areas please contact Marko on 07767 664186 or email him on or visit

We run regular nutritional workshops and 1-2-1 nutritional consultations at Meridian Leisure Centre, Station Sports Centre, Horncastle Swimming Pool & Fitness Suite and Embassy Swimming Pool & Fitness Suite.

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