Intermittent fasting has become a popular weight loss strategy in recent years. Many studies claim that this eating pattern not only helps shed pounds but also improves metabolism and heart health. Discover insights from an expert about the fasting diet, its potential health benefits and possible side effects.

Intermittent fasting involves alternative periods of fasting and eating. A commonly followed method is time-restricted eating, where individuals follow the 16/8 method (fasting for 16 hours and then eating during an eight-hour window), or the 14/10 method (14-hour fast followed by a 10-hour eating window). There are also other approaches like alternate-day fasting, twice-a-week fasting and a once-a-week 24-hour fast.

Intermittent Fasting Benefits

"Some preliminary studies suggest that intermittent fasting can help with metabolic health because of its effects on insulin sensitivity and blood sugar regulation. Others have found that intermittent fasting can help with cellular repair because of increased autophagy, a process where cells remove damaged components," Michelle Routhenstein, a registered dietitian and preventive cardiology nutritionist and owner of Entirely Nourished, told Medical Daily.

"However, more long-term studies are needed to determine the true benefits of intermittent fasting in the long haul. The long-term effects of intermittent fasting on metabolism, hormone balance and overall health are still subjects of ongoing research, and comprehensive conclusions are challenging to draw," she added.

Weight Loss

Intermittent fasting is considered an effective weight loss tool by many, as it typically allows people to have fewer meals that help reduce their total calorie intake. Additionally, the fasting diet promotes hormone functions, such as insulin regulation, which is crucial for effective weight loss.

A 2020 study suggests that It can help in weight loss of 0.8% to 13.0% of baseline weight.

Blood Sugar Control

In addition to weight loss benefits, some studies indicate that intermittent fasting can help reduce insulin resistance and blood sugar levels. The results of a small-scale study in 2022 even suggest that it can help with diabetes remission.

However, intermittent fasting is generally not recommended for people with type 2 diabetes. People who are on diabetes treatment need adjustments in their medications if they need to try time-restricted eating. It is always advisable to seek guidance from a health care professional, especially for individuals with diabetes, before making any changes to their dietary habits.

Heart Health

A research overview published in the National Library of Medicine in 2019 examined the effects of intermittent fasting on the cardiovascular system. The study found that intermittent fasting can help reduce total cholesterol, triglycerides and LDL cholesterol while also lowering both systolic and diastolic blood pressure — key factors influencing heart health.

Side Effects

According to Routhenstein, the most common side effects of intermittent fasting include hunger, irritability, headaches, fatigue, nutrient deficiencies and potential impacts on sleep.

"Intermittent fasting may not be suitable for individuals with certain medical conditions, including diabetes, cardiovascular issues, gastrointestinal disorders, kidney disease, thyroid disorders, mental health conditions and those on specific medications. Medications may require consistent food intake for proper absorption, and fasting could interfere with medication effectiveness," she cautioned.

It is also not advisable for pregnant and breastfeeding women, underweight people, individuals with a history of eating disorders, those who have experienced low blood sugar (hypoglycemia) and those diagnosed with end-stage liver disease.

Routhenstein recommends seeking guidance from a health care professional like a registered dietitian nutritionist before embarking on the diet regimen. "They will evaluate your health status, medication needs and potential interactions with fasting practices, tailoring recommendations to promote your optimal health," she explained.

Choosing a Fasting Schedule

According to a recent large-scale trial, restricting eating to a 10-hour window during the day reduces hunger and improves mood and energy. The study also found that people who were consistent with this eating window reaped greater benefits compared to those who changed them daily.

Routhenstein, however, suggests selecting a personalized fasting schedule with long-term sustainability in mind. "When selecting a fasting schedule, it's crucial to prioritize long-term sustainability. Opting for a very short window may result in nutrient deficiencies and a high metabolic load, potentially impacting cardiometabolic health negatively. If you take medications that necessitate food intake, refrain from fasting during those periods to ensure their effectiveness," she said.

"A new study showed delaying the first meal of the day by an extra hour was linked to an increased risk of overall cardiovascular disease, making the window of time for intermittent fasting important in its use," she added.