Intermittent fasting and weight loss: What does the science say?
For centuries fasting has been the cultural norm for people all around the world. The purpose for which has varied from health benefits to religious or spiritual practices. Dr Michael Mosely was the modern-day catalyst for the immensely popular intermittent fasting, also known as time restricted feeding. The most common form of which involves fasting for 16 hours a day and restricting food to just 8 hours. Weight loss and metabolic health are just some of the reported benefits of intermittent fasting. But what does the science really say, and how does it compare to the long list of alternative diets making similar claims?
As a dietitian helping individuals achieve their weight loss goals, intermittent fasting is a commonly discussed topic. Particularly regarding its effectiveness as a strategy to lose weight. In short, intermittent fasting is indeed a legitimate approach to losing weight, as many people have testified. But the real question remains… are weight loss results better when compared to other popular diets? To answer this, a review of scientific literature was conducted in 2019 involving 11 randomized control trials that compared intermittent fasting to calorie-controlled diets. It found that intermittent fasting offered no significantly better results in terms of weight loss. Randomised control trials are considered the gold standard of science, meaning this conclusion is very telling.
But before we throw cold water on intermittent fasting completely, research does indicate the potential role fasting plays at cellular level, independent of weight loss. The relationship between immune system strength and longer-term fasting has been established for some time. Studies have even investigated at the role of fasting to support those undergoing chemotherapy, with fascinating outcomes. More specifically, intermittent fasting such as the 16/8 approach, appears to play a deeper role in cellular expression with significant implications for metabolic health. Improved insulin sensitivity and blood lipids are just two examples of this.
What about fasting in terms of my personal observations? Whilst I have never committed to fasting myself, as a dietitian based on Adelaide, I’ve observed longer term outcomes of many who have. And for some it’s worked very well. Yet for other clients we have achieved far better results turning our attention away from intermittent fasting to a more frequent meal pattern. This tells me that, like most diets and eating patterns, there is no one size fits all when it comes to fasting. Fasting is not for everyone.
My advice for those who decide to forge ahead with fasting is to maintain a regular meal pattern within your eating window. In other words, try avoiding long periods between meals or snacks. Eating 4-5 times within your window is preferrable to 2-3 times in terms of metabolic output, based on my observation.
Finally, it’s important to point out that everyone experiences a daily fast of some duration. Hence the term breakfast as the meal to break one’s fast. Fasting overnight is an important time to allow our body to rest, repair and recover. Whether you choose to actively fast or not, prior to bed allowing yourself 90 minutes or more without food will likely provide several health and metabolic benefits. Not to mention a better night’s sleep!
Written by David Finnin
David is an Accredited Dietitian and Nutritionist based in Adelaide, who specialises in weight loss, food intolerance and chronic health
