A healthy gut helps you to lose weight and keep the weight off

What do Gut Bacteria do?

Our gut bacteria are the first to interact with the food that we eat and they generate messages to our central nervous system (gut-brain axis) and our immune cells, influencing our body weight.

Mouse studies (1) have shown that when you replace or remove their gut bacteria, you can alter their body weight, proving that gut microbes have a role to play in obesity. Faecal transplants (3) have been shown in rats to be successful for weight management. Faecal transplants involve harvesting gut bacteria from healthy individuals and administering them to people who are in health difficulty with a lot of excess bodyweight. Faecal transplants have been performed in Ireland in Tallaght hospital to help with C. Difficile infections and with success.

Studies have also shown that eating a high-fat and high-sugar diet, even for a short period of time, alters your gut bacteria, influencing your body weight. (2) The most additive foods are a combination of sugar and fat in processed form(4) such as a McDonnell burger. The bun is sugar, the burger is fat and then salt, flavours and additives and it really soft, easily and quickly digested. For the health of gut bacteria, your priority is to avoid processed food.

There are trillions of bacteria of about 1000 species living inside you and they have a very busy job. Have a read of what your gut bacteria do…

  • they produce short chain fatty acids [scfa] from the  fibrous foods we eat but if you eat a low fibre diet, this may be why your gut is unhappy. Fibre slows the movement of food out of the stomach which keeps you fuller for longer and it requires chewing, sending strong satiety signals to the appetite centre in the brain.
  • these scfa’s
    • regulate fat and sugar storage regulating body weight
    • heal and repair the gut wall,  [butyric acid]
    • controls colon cell replication thereby reducing colon cancer risk
    • help to lower cholesterol  levels [acetic acid, propionic acid]
    • discourage the growth of unfavorable bacteria and yeast such as candida albicans [lactic acid]
  • they produce vitamins – B’s and K and release valuable plant polyphenols from foods – quercitin, grape seed extract, rutin are examples.
  • they help our immune cells to develop a tolerance to foods, reducing food sensitivities
  • they identify dangerous bacteria and viruses, protecting us
  • they improve the breakdown of lactose
  • they promote a regular bowel movement helping us to avoid constipation or diarrhoea, gas, bloating, indigestion and cramp
  • they bind heavy metals for elimination, helping detox
  • they biotransform plant oestrogens reducing the risk of breast cancers
  • they produce gas while doing all these jobs

The below video is 30 minutes and tells a fantastic GUT Bacteria story by the leading Food Biochemist in the world – Listen to it from 7 & 8 mins in.

Joan Moloney,  BSc is a nutritional therapist based in South Dublin, Ireland. She specialises in weight loss. If you are interested in losing weight and need someone with a knowledge of gut health, contact me


1. Wostmann et al. (1983) 

2. David et al., 2014

3. Ley et al., 2006Turnbaugh et al., 2009Smits et al., 2013

4. Schulte E et al (2015)

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