One thing constant about science is that it keeps evolving. The more we research, the more we realise that many of the things that we took for granted as facts of science aren’t completely true. For instance, there was a time after WWII when lead was considered good for health and thought to have superpowers to prevent diseases. It was even added in foods and food products to make them “healthier,” not unlike how several companies and products claim to boost your immunity and kill bacteria and virus during these covid times. Over time, further research found that lead was lethal for the human body and today we know better than to add lead to anything we use in life let alone ingesting it. Today we’re going to look at metabolism and how our understanding of this has evolved. Advancements in science and recent research have revealed new facts about our metabolism and the weight-diabetes link.
A study on metabolism titled Daily Energy Expenditure Through The Human Life Course published in the Science journal in August is a case in point. It presented evidence that renders redundant the most popular thing we know and accept about metabolism—that it slows down with age. More than 80 scientists analysed data from over 6,000 individuals. They found that contrary to the widely accepted theory, our metabolism does not slow down in our middle years. The study found that metabolism, which is the energy expended by the body, steadily increases after birth and by the age of one year is more than 50% higher than an adult’s. After that point, the energy expenditure “gradually declined until young individuals reached adult characteristics,” the study noted, adding that thereafter our metabolism remains almost the same between the ages of 20 and 60, and starts slowing down only around the age of 60. This means that you will burn calories as efficiently at the age of 25 as when you're 55.
A separate study presented at the European Association for the Study of Diabetes in September this year found that people of normal weight could push type 2 diabetes into remission by losing 10-15% of their body weight. The study presented by a leading diabetes expert from Newcastle University also noted that people risk developing type 2 diabetes if they can no longer fit into jeans they wore at the age of 21.
As with metabolism, for long the world of medicine has believed that type 2 diabetes among people of normal weight was caused by other factors. The study included 12 type 2 diabetes people with an average body mass index (BMI) of 24.5 and they were put on three rounds of a two-week weight loss programme. At the end of the programme, eight people who lost 10-15% of their weight, also reduced the fat in their liver and pancreas and improved the functioning of insulin-producing cells in the pancreas. These people were able to remit their type 2 diabetes, had their blood sugar levels under control and did not need any medication anymore.
These findings mean that we might need to rethink our approach to health, food, exercise and definitely think twice before believing what our activity trackers and smart watches tell us about calories burnt. The new metabolism study contends that a person who does nothing all day burns the same amount of calories throughout the day as someone who leads an active life. This is information that could send the entire health, fitness, nutrition and wellness industry, including the health tech companies and activity trackers, into a tizzy. The health tech companies will need to rework their algorithms so the trackers remain accurate.
For fitness and health professionals, designing a weight loss routine is likely to change dramatically. A 2018 study published in Obesity Review found that hunter-gatherers in Tanzania lead a very active life with more than 100 minutes of moderate to vigorous physical activity but their “daily energy expenditures (metabolism) are similar to industrialised populations,” (meaning people like us living in cities). The researchers on that study also found that the hunter-gatherers have excellent cardiovascular health, there is low prevalence of obesity among them and they have modest mean body fat percentages (women: 24-28%, men: 9-18%) that would put “fit” individuals in the industrialised world to shame.
It means exercise doesn’t impact your metabolism. Now that we know exercise doesn’t increase your metabolism, weight loss programmes would need to focus a lot more on food. With metabolism cancelled out, middle age weight gain can be pinned down to genetic reasons, hormones, stress, sleep and diet. “The reason we’re gaining weight is not only because there’s more food available than we have evolved to expect, but because they’re modern, industrialised foods, designed to be overeaten,” Herman Pontzer of Duke University in North Carolina, USA, and the lead author of the metabolism study told the Guardian recently.
Given that the Newcastle University study demonstrated that type 2 diabetes, a disease that plagues large numbers of people across the world, could be pushed back by something as straightforward as weight loss, the new findings on metabolism are likely to force the health professionals to focus more on food than exercise for shedding the extra kilos. However, even if exercise doesn’t make you slim, it still makes you fit, strong and improves your cardiovascular and overall health. So, instead of using the new findings as an excuse to not exercise, use it as vital information that exercise coupled with better food habits will not only keep you healthy, fit and diabetes-free but also help you achieve your weight goals. Just that now you can’t blame lack of results on metabolism anymore.
Shrenik Avlani is a writer and editor and co-author of The Shivfit Way, a book on functional fitness.