Intermittent fasting is safe and effective for weight loss and heart health

A group of scientists has found that intermittent fasting, which involves limiting the hours of eating and extending the hours of fasting each day, is an effective way to lose weight and improve heart health for people dealing with obesity.

Their study, published in Nature Medicine, suggests that eating your last meal before 5 p.m. and skipping dinner could be particularly beneficial, especially after periods of overindulgence like the holidays.

Obesity is a growing problem worldwide. In Spain, about 70% of men and 50% of women are either overweight or obese. This condition is linked to serious health issues, including type 2 diabetes, high blood pressure, heart disease, and even certain types of cancer.

The rise in obesity is not only affecting people’s quality of life but also putting a strain on public healthcare systems. Scientists are now searching for simple, effective ways to combat this problem, which is increasingly being classified as a disease.

Traditional calorie-restricted diets are known to help with weight loss and heart health. However, these diets can be hard to follow in the long run, leading many people to abandon them and regain the weight they lost. In response, researchers are exploring new strategies, such as intermittent fasting, to provide easier alternatives.

Intermittent fasting alternates periods of eating with periods of fasting, which can last hours or even days. A popular approach is time-restricted eating, where the eating window is reduced, and fasting is extended each day.

For example, in Spain, people typically eat their first meal around 7–8 a.m. and finish dinner around 9–10 p.m., leaving a 12–14 hour eating window.

With time-restricted eating, this window is shortened to 6–8 hours, and people fast for 16–18 hours. This schedule aligns better with the body’s natural rhythms, which can stabilize biological processes and reduce risks for conditions like obesity and diabetes.

What the Study Found

To test the effects of intermittent fasting, researchers conducted a 12-week study involving 197 participants aged 30–60, with equal numbers of men and women.

Participants were randomly divided into four groups: a control group (no fasting), an early fasting group (eating from 9 a.m. to 5 p.m.), a late fasting group (eating from 2 p.m. to 10 p.m.), and a self-selected fasting group, where participants chose their own 8-hour eating window, typically from 12 p.m. to 8 p.m.

All participants also received a nutrition education program on the Mediterranean diet and healthy lifestyle habits, regardless of their assigned group. The study, conducted in Granada and Pamplona, Spain, is one of the largest of its kind.

Key Results

The study found that intermittent fasting led to greater weight loss compared to the control group, where participants maintained a 12-hour or longer eating window. On average, those in the fasting groups lost 3–4 kilograms over the 12 weeks.

Among these groups, the early fasting participants showed the most significant reduction in subcutaneous abdominal fat—the fat stored just under the skin.

Early fasting also had a notable impact on glucose regulation. Participants in this group showed improved fasting blood sugar levels and better overnight glucose management, measured using continuous glucose monitors.

This improvement is significant because better glucose regulation reduces the risk of developing type 2 diabetes and other metabolic disorders.

Interestingly, the study found no major differences in the reduction of visceral fat—the fat around internal organs—between the fasting groups and the control group. However, the overall benefits of intermittent fasting on weight loss and blood sugar management were clear.

Safe and Sustainable

The researchers noted high adherence rates across all fasting groups, and no serious side effects were reported. This indicates that intermittent fasting is not only effective but also safe for managing weight and improving cardiovascular health in overweight and obese individuals.

Early fasting, in particular, appears to optimize glucose levels and support metabolic health by allowing the body more time to process nutrients during fasting periods. This makes it a promising strategy for preventing conditions like type 2 diabetes while helping people maintain a healthier weight.

In conclusion, intermittent fasting offers a practical and effective approach to tackling obesity and related health issues. With its simplicity and lack of adverse effects, it could play a vital role in improving the outcomes of nutritional interventions for individuals struggling with their weight.

If you care about weight loss, please read studies that hop extract could reduce belly fat in overweight people, and early time-restricted eating could help lose weight.

For more information about weight loss, please see recent studies that Mediterranean diet can reduce belly fat much better, and Keto diet could help control body weight and blood sugar in diabetes.

The research findings can be found in Nature Medicine.