Wellness

The Key To Weight Loss May Lie In The Gut

The question of why some can lose and maintain weight while others cannot has long baffled doctors. Australian researchers at the Garvan Institute believe the answer may lie in personalised dieting and the gut.

By Lara Robertson

Wellness

The question of why some can lose and maintain weight while others cannot has long baffled doctors. Australian researchers at the Garvan Institute believe the answer may lie in personalised dieting and the gut.

By Lara Robertson

Researchers believe they may have found the answer to why some people can lose and maintain weight while others cannot. They believe the answer lies in the gut. Australian researchers at the Garvan Institute are currently undertaking the PREDICT clinical trial, led by Dr Dorit Samocha-Bonet and Professor Jerry Greenfield. While the study focuses on improving the treatment of diabetes and prediabetes, the findings could also help those who struggle with their weight, and could potentially revolutionise the longstanding one-size-fits-all approach to dieting and medicine.

The PREDICT study draws on research conducted by their collaborators at the Weizmann Institute of Science in Israel, which found gut microbiota plays a significant role in determining what foods will cause blood sugar levels to spike. This research found different foods can have dramatically different effects on blood sugar levels for different people. Even more surprising were findings that people who share similar blood sugar levels after eating the same food also have similar signatures of gut microbiome, the collective genomes of the microorganisms.

Expanding on this research, the PREDICT study is looking at how the gut microbiota of individuals diagnosed with type 2 diabetes or undiagnosed prediabetes reacts to metformin, the first-line medication for the treatment of type 2 diabetes and prediabetes.

“Some 20 to 40 per cent of people with diabetes or prediabetes do not respond to this medication,” said Dr Samocha-Bonet. “Metformin has been around for 60 years now, but we’re still figuring out how it works. What we would like to achieve in the PREDICT study, is to see if we personalise the diet based on the gut microbiota, if we get a better response to metformin. And secondly, we would like to find out whether we can predict who is more likely to respond to metformin, based on their gut microbiota composition, as well as the traditional markers, like body weight and body fat.”

A Personalised Approach

The Garvan Institute research team believes the study’s findings may point towards establishing a more personalised approach to medicine and diet, rather than a one-size-fits-all approach that works for some patients and not others.

Dr Samocha-Bonet drew this hypothesis from her extensive 30-year experience as a clinical dietician. She saw many patients who were unable to maintain long-term weight loss, those that suffered from prediabetes and type 2 diabetes were unable to improve their condition despite losing weight.

 

“What we should be asking is ‘What diet is good for you to lose weight?’ because we know it’s going to be different from one person to another.”

 

“Personalised diet in any field is a very young area of research, so we’re still learning,” Dr Samocha-Bonet said. “What we do know is that we should probably stop asking the question, ‘What diet is good for human beings?’ or ‘What diet is good for a person with type 2 diabetes?’ What we should be asking is ‘What diet is good for you to avoid type 2 diabetes?’ or ‘What diet is good for you to lose weight?’ because we know it’s going to be different from one person to another.”

If you want to find out what gut microbiota you have, Dr Samocha-Bonet said you can go online, where a number of companies allow you to send in a sample of your gut microbiota, which is simple to collect. You’ll be sent back a breakdown of the composition of microorganisms in your gut that are typically associated with health, or those that are associated with type 2 diabetes, being overweight or obese.

Illustration: Patti Andrews

Probiotics Are Not The Savior We’ve Been Looking For

Unfortunately, Dr Samocha-Bonet said researchers aren’t quite sure which foods improve your gut microbiota. “At the moment we don’t know what you need to eat to actually transform your gut microbiota from the bad guys to the good guys,” she said. “What we do know is that it’s probably very individual, and you may have the same makeup of bacteria and organisms in your gut as another person, but you will very likely not benefit from the exact same diet as them.”

Nonetheless, Dr Samocha-Bonet still recommends incorporating fermented foods like sauerkraut and yoghurt into your diet. But if you’re thinking about rushing to the pharmacy to pick up some probiotic pills, she said studies are inconclusive about their effectiveness for gut health.

“Eating foods with the cultures of microorganisms is good for our gut microbiota,” she said. “As to whether it’s good for us to take probiotics in the form of a pill, for certain conditions, like gastrointestinal problems, it is, but in the field of diabetes and obesity, for every study that says yes, take a probiotic, there’s another study that negates that, saying it didn’t have any effect.”