Fasting diets have witnessed a surge in popularity in recent years due partly to celebrity endorsement, increased awareness of fasting benefits, and a growing body of research that supports this dietary intervention. These nutritional protocols come in many variations, including 5:2 – during which five days of unrestricted eating are followed by two days of fasting – 18:6 – 18 hours of fasting per day with a 6-hour eating window – and alternate-day fasting – which consists of fasting every other day.
A large body of scientific evidence has proven that regular, short-term fasting can improve overall health, promote weight loss, benefit gut health, and enhance cognitive function. While there are different approaches and purported benefits to the popular dietary trend, many misconceptions remain. Read on to discover the popular myths about fasting and the science-backed facts behind them.
5 Common Myths About Fasting
Myth 1: You can eat anything you want during eating window hours.
Many individuals are drawn to fasting and fasting-mimicking diets for the promise of being able to engage in unrestricted eating during their scheduled eating hours – and still lose weight. This is also one of the most prevalent myths surrounding fasting.
While this may be true for individuals who consume all of their desired foods but remain in a calorie deficit, it is often not the case. Instead, some individuals overeat during the eating window, especially when they adopt the practice as a temporary weight loss solution.
Fact: The eating window is meant for a well-balanced diet that includes whole grains, lean proteins, healthy fats, fruits, and vegetables. For those who maintain a calorie deficit despite unrestricted eating, weight loss is possible.
Myth 2: Intermittent fasting makes you lose muscle.
The belief that intermittent fasting (IF) spurs muscle atrophy is also common. Although muscle loss may be a side effect of any dietary intervention, there is no scientific evidence that suggests fasting does so more than any other approach. In fact, fasting diets are favored among bodybuilders as they help them maintain muscle alongside a low body fat percentage.
Contrary to this myth, research indicates that intermittent fasting may be more beneficial for maintaining muscle mass. One review found that fasting resulted in a similar amount of weight loss as continuous calorie restriction but less muscle mass reduction.
Meanwhile, a separate study showed a modest increase in muscle mass in participants who consumed all of their calories during one large evening meal versus those who ate more frequently.
Fact: Fasting can actually support muscle maintenance during weight loss.
Myth 3: Frequent, small meals can make you lose weight.
Eating frequent meals has been associated with a boosted metabolism, resulting in increased weight loss. Both concepts are myths. Decreasing or increasing meal frequency does not affect the total number of calories burned – the most important factor in weight loss. At the same time, individual metabolic rate is not influenced by the frequency or size of meals. A study of adults with obesity compared the effects of eating 3 and 6 meals per day, finding no difference in weight, fat loss, or appetite among participants.
Fact: Meal frequency does not impact weight loss.
Myth 4: Breakfast is a critical component of the day.
The idea that breakfast is the most important part of the day is part of an ongoing myth that associated skipping breakfast with excessive hunger, food cravings, and weight gain. As the research mentioned above has shown, there is no link between weight and meal timing. A study of overweight and obese adults found that eating breakfast had no effect and made no difference in weight.
However, it is essential to note that there is individual variability; for instance, children and teenagers have higher nutrient needs and benefit from eating breakfast. This may also be the case for other individuals who feel or perform better after eating breakfast.
Fact: While some people may benefit from eating breakfast, the meal is not a factor in weight loss and can often be skipped without negative consequences.
Myth 5: Intermittent fasting slows down the metabolism.
The fifth and final myth surrounding fasting is that it may lower the resting metabolic rate. On the contrary, fasting has been shown to boost the metabolism and even promote its adaptability when done for short intervals.
Fasting windows provide the body with the time and rest it needs to support chemical and hormonal processes that enhance metabolism optimally. Levels of metabolic regulators such as norepinephrine and growth hormone increase alongside fasting practices.
Additionally, the hormonal system ensures that the basal metabolic rate remains high precisely when no energy is supplied – a critical factor supporting human survival. As such, fasting can promote metabolic flexibility or the ability for the body to adapt to changes in fuel source and availability with ease.