Intermittent fasting has emerged as a popular weight-loss strategy in recent years, and new research suggests it may be just as effective as traditional calorie restriction diets – with one method standing out as particularly beneficial.
Intermittent fasting involves limiting the hours in which food is eaten each day, prompting the body to use stored fat for energy after exhausting its glucose reserves. Numerous health experts, including those at Johns Hopkins Medicine, have previously highlighted the health benefits of this dietary approach.
Obesity remains a major public health concern, affecting two in five adults in the United States and costing the American healthcare system around $173 billion annually. Excess body weight significantly raises the risk of chronic diseases, such as heart disease and type 2 diabetes.
In a recent study, researchers from the Harvard T.H. Chan School of Public Health and several international institutions conducted an analysis comparing various intermittent fasting methods. Published in The BMJ, the study included data from over 6,500 adults across 99 clinical trials, most of whom were obese and had pre-existing health conditions.
The study found that alternate-day fasting, where individuals fast every other day, provided superior health benefits compared to standard calorie restriction and other intermittent fasting techniques.
Harvard researchers highlighted, “Among all intermittent fasting methods studied, alternate-day fasting – where a person eats normally one day and completely abstains from food the next – was shown to be the most effective.”
Participants practising alternate-day fasting achieved greater weight loss, averaging 2.8 pounds (around 1.3 kg) more than those on traditional calorie-restricted diets. This fasting approach also led to significant improvements in key health markers linked to cardiovascular disease and type 2 diabetes risk, including reductions in waist circumference, cholesterol, triglyceride levels, and inflammation measured by C-reactive protein.
Additionally, alternate-day fasting was associated with lower levels of total cholesterol and LDL (“bad”) cholesterol, reducing risks linked to heart attacks and strokes.
However, researchers noted the observed differences in weight loss were still below the clinically significant threshold – defined as at least 4.4 pounds (2 kg) – for individuals with obesity. Longer trials are therefore required to better understand the long-term effectiveness of intermittent fasting and its clinical implications.
Zhila Semnani-Azad, the study’s lead researcher, emphasised caution, stating, “Intermittent fasting, despite its promising results, may not be suitable for everyone. Before making significant dietary changes, it is essential to consult healthcare professionals and consider personal medical history, lifestyle, social circumstances, and potential for sustained adherence.”
This research contributes valuable insights into how intermittent fasting could help address obesity and associated health risks, though further studies are needed to fully confirm and understand its long-term benefits.