Intermittent fasting: The diet trend science keeps backing

Source: Nida Al Watan

In recent years, intermittent fasting has become one of the world’s most popular dietary trends, not only among people seeking weight loss, but also among those aiming to improve their overall health and prevent chronic diseases. As its popularity has grown, so have the studies and scientific research attempting to understand its real effects on the body and whether it is more effective than traditional calorie-restriction diets. A recent study published in the medical journal “The BMJ,” conducted by researchers from the Harvard T.H. Chan School of Public Health, found that intermittent fasting may be just as effective as traditional diets in promoting weight loss and improving indicators of heart and metabolic health, with some forms potentially delivering even better results.

Intermittent fasting is a dietary pattern based on alternating between specific periods of eating and periods of fasting. Unlike traditional diets that mainly focus on food quality or calorie intake, intermittent fasting focuses primarily on the timing of meals.

There are several forms of intermittent fasting, the most common being:

1. The 16:8 Method

This method involves fasting for 16 hours daily while eating only within an 8-hour window. For example, a person may eat between 12 p.m. and 8 p.m., then refrain from eating until the following day.

2. The 5:2 Method

A person eats normally for five days a week, while significantly reducing calorie intake or fasting on two non-consecutive days.

3. Alternate-Day Fasting

Known as “Alternate Day Fasting,” this method involves fasting completely or consuming very few calories every other day, while eating normally on the following day. The recent study found that this approach was the most effective among all the dietary methods examined.

What did the recent study find?

Researchers conducted a broad scientific review and comprehensive analysis of 99 clinical studies involving more than 6,500 participants. The aim was to compare the effects of intermittent fasting with traditional low-calorie diets, as well as unrestricted eating patterns. The average body mass index (BMI) among participants was around 31, meaning most were overweight or obese. Approximately 90% also had pre-existing health conditions such as diabetes, high blood pressure, or lipid disorders.

The findings showed that:

- Intermittent fasting and traditional diets were nearly equal in terms of weight-loss effectiveness.

- Both approaches were significantly more effective than following no diet at all.

- Alternate-day fasting delivered the best results, leading to an additional average weight loss of around 1.3 kilograms compared to traditional calorie-restriction diets.

- Intermittent fasting also helped improve health indicators linked to heart and metabolic health.

How does intermittent fasting help with weight loss?

When the body goes without food for a relatively long period, it begins using stored energy reserves, particularly stored fat. Reducing the number of eating hours may also naturally lower the total number of calories consumed throughout the day. In addition, intermittent fasting may help:

- Improve insulin sensitivity.

- Reduce feelings of hunger over time for some individuals.

- Regulate blood sugar levels.

- Enhance fat burning.

However, it is important to note that results vary from person to person, and the success of the diet also depends on the quality of food consumed during eating periods.

Intermittent fasting and health

The benefits observed in the study were not limited to weight loss. They also included several indicators linked to cardiovascular health, such as:

- Reduced waist circumference

- Fat accumulation around the abdominal area is associated with an increased risk of heart disease and diabetes. Intermittent fasting showed a noticeable ability to reduce this type of fat.

- Improved cholesterol and triglyceride levels

- Intermittent fasting helped lower triglycerides and harmful cholesterol levels in some participants, potentially reducing the risk of atherosclerosis.

Reduced inflammation

Researchers observed lower levels of C-reactive protein (CRP), a marker associated with chronic inflammation and heart disease.

Is intermittent fasting suitable for everyone?

Despite the positive findings, researchers emphasized that intermittent fasting is not the ideal choice for everyone. Some individuals may struggle to maintain it long term, while it may be unsuitable for certain medical conditions. Groups that should consult a doctor before trying intermittent fasting include:

People with diabetes, especially those using insulin.

Pregnant and breastfeeding women.

Individuals with eating disorders.

People who are underweight or malnourished.

Individuals taking medications that require food at specific times.

Some people may also initially experience symptoms such as headaches, fatigue, dizziness, difficulty concentrating, irritability, or mood swings. These symptoms often improve gradually as the body adapts.

Intermittent fasting and food quality

Some believe intermittent fasting allows unrestricted eating as long as fasting hours are respected, but this belief is inaccurate. Even with intermittent fasting, food quality remains essential for achieving health benefits. Excessive consumption of sugar, fast food, and high-calorie beverages during eating periods may significantly reduce the diet’s effectiveness. Therefore, it is recommended to focus on:

Fruits and vegetables.

Healthy proteins.

Whole grains.

Healthy fats such as olive oil and nuts.

Drinking sufficient amounts of water.

Intermittent fasting and exercise

Intermittent fasting can be combined with physical activity for better results, but attention should be paid to workout timing and intensity. Some individuals prefer exercising right before breaking their fast to maximize fat burning, while others feel more energized when exercising after eating. It is also recommended to focus on:

Resistance training to preserve muscle mass.

Walking and maintaining daily activity.

Avoiding extremely intense workouts when first starting the diet.

Are the results guaranteed?

Despite the encouraging results, researchers noted that most of the analyzed studies lasted less than 24 weeks, meaning information about long-term effects remains limited. Scientists still need further studies to determine:

Whether people can maintain the diet for years.

Its long-term effects on heart health and hormones.

Whether weight loss can be sustained after stopping the diet.

Many diets may produce excellent short-term results, but the real challenge lies in maintaining them without feelings of deprivation or exhaustion. Recent research suggests that intermittent fasting may be an effective approach for weight loss and improving some metabolic and cardiovascular health indicators, particularly when applied in a balanced and well-planned way. Studies have shown that some forms, such as alternate-day fasting, may produce better results than traditional low-calorie diets. However, no single diet works for everyone. The success of any dietary plan ultimately depends on a person’s ability to maintain it and how well it fits their health condition and lifestyle. The ultimate goal remains achieving a healthy and sustainable lifestyle, rather than simply losing weight for a short period.