Scientists have answered a fundamental question around the ‘gain weight, lose weight, gain weight’ phenomenon. It seems that your microbiome (the home for your trillions of good and bad intestinal gut bacteria microbes) needs to be ‘rebuilt and reset’ after you have lost the weight. Weight loss alone is not enough.
“This may explain more than some of our failure to control weight by dieting. I know this is a sobering thought but once you get rid of the differences in the microbiome then you close this window of risk. We’ve shown in obese mice that following successful dieting and weight loss, the microbiome retains a ‘memory’ of previous obesity. This persistent microbiome accelerated the regaining of weight when the mice were put back on a high-calorie diet or ate regular food in excessive amounts”
Dr Eran Elinav, Immunologist, Weizmann Institute of Science, Israel.
Time and effort
The scientists found that it was not just the return to bad eating habits that caused the weight gain (though this is the primary cause in almost all cases), but actually the ‘obesity memory’ of the microbiome itself. It seems a key reason you are pulled back into bad eating habits (alongside a lack of sleep, food addictions, being time poor and the obesogenic environment we live in of course), is that your microbiome heads back to what it knows; being overweight. The longer you are overweight, the longer it will take to get back to a healthy body size and a new microbiome. This is a simple answer for why, from my real world experience, I have always said that it takes around a year to get well. Sometimes much longer.
“This is one of the first studies to show that gut bacteria could actively drive weight gain, rather than simply being associated with it”
Simon Cork, medical researcher, Imperial College London.
What did the scientists discover?
In the study published in Nature, Eran Elinav, an immunologist at the Weizmann Institute in Israel and lead author, alongside colleagues, looked at a variety of mice. Some were lean, some were obese and some were formerly obese and now slim. These researchers found that in the obese or formerly obese mice, the changes to the makeup of the microbiome stayed for five times the length spent dieting. This predisposed the mice to a rapid regaining of the weight.
The study details
A control group of mice were fed a high fat diet until they became overweight or obese. They were then changed to a nutritious diet until they hit the healthy blood sugar and weight measurements of a controlled group of mice that had never been overweight or obese. The researchers discovered that the formerly overweight or obese mice still retained an unhealthy microbiome after they had lost the weight. This microbiome was very different to the mice that had never been overweight or obese.
The bad news
After both groups of mice were refed the high fat diet, the formerly obese or overweight mice gained weight much faster than the mice that had never been overweight. When the healthy mice were “seeded with bacteria from the obese group”, they then gained weight far more rapidly.
The good news
The longer the formerly overweight or obese mice stayed on the healthy nutritious diet, the healthier their microbiome became. It took around five times the length that than they had been dieting but if they stuck to the diet long enough, their bacterial composition of their microbiome changed for good. The ‘memory’ of extra weight or obesity disappeared. Their body shape changed for good.
My gut feeling
Ironically, the ‘gut instinct’ from my microbiome, on teaching people that it is a much longer journey than the currently trendy “12 weeks” type weight-programmes, seems to be pretty much correct. This is also common sense, just explained in a scientific way. The longer you carry extra weight, the more your microbiome changes for the worse, the longer it takes to get well again.
The bottom line advice from me remains the same
You are in control of your genetics and this is done through your microbiome. Your microbiome is mostly dictated to by your diet, lifestyle and environment. You change these and your microbiome changes and hence your genetic expression changes. This is how you are in charge of your genetic expression and your health and longevity.
You are what you eat, do, think, feel and behave.
Jason wishes to deeply thank, acknowledge and recognise the effort and contribution that the PIF Foundation has provided on a voluntary basis since 2014, as we educated, motivated and inspired change that helps transform the health, vitality and longevity of people all over the world.