Intermittent fasting has become one of the most popular eating trends, especially on social media. For adults, some research suggests it can help with weight loss. But a Canadian study raises an important concern about what fasting may mean for teenagers and young adults.
What is intermittent fasting?
Intermittent fasting is a pattern of eating that alternates between periods of eating and periods of not eating. Some people limit eating to a set window each day, while others cut back sharply on certain days of the week. It’s often promoted for weight loss and metabolic health, and it’s widely discussed online, where many young people first encounter it.
How the study worked
Researchers led by Kyle Ganson at the University of Toronto analyzed data from the Canadian Study of Adolescent Health Behaviors, which included 2,762 adolescents and young adults. Participants answered questions about whether they had practiced intermittent fasting in the past year, along with detailed questionnaires about their attitudes toward food, weight and body shape, and about eating disorder behaviors. The study was published in the journal Eating Behaviors.
What the researchers found
- Fasting was very common. Nearly half of young women, about 38% of young men, and about half of transgender and gender-nonconforming participants said they had tried intermittent fasting in the past year.
- Fasting was linked to eating disorder thoughts and behaviors in every group. Young people who fasted were more likely to report unhealthy attitudes about eating, weight and shape.
- The link was especially strong among young women, where fasting was associated with a range of eating disorder behaviors, including binge eating and compulsive exercise.
- Among young men, fasting was particularly linked to compulsive exercise.
The study shows an association, not cause and effect. It’s possible that young people already struggling with their relationship to food are more drawn to fasting. Either way, the authors say health professionals and families should be aware of the connection, especially as these trends spread on social media.
Why young people may be more vulnerable
Adolescence and young adulthood are when eating disorders most often begin. Bodies are still growing and need steady, adequate nutrition. Rigid rules about when and how much to eat can make it easier for unhealthy patterns to take hold, and fasting can be hard to tell apart from restrictive eating.
What this means for families and young people
- Talk about what they’re seeing online. Ask teens what diet advice they’re coming across, and discuss it without judgment.
- Focus on nourishment, not rules. Regular, balanced meals that include a variety of foods support growth, energy and mood.
- Check with a professional first. Young people considering any structured eating plan should talk with a doctor or registered dietitian.
- Know the warning signs. These include skipping meals or entire food groups, intense focus on weight or body shape, eating in secret, compulsive exercise, and withdrawing from social events that involve food.
- Get help early. Eating disorders are serious but treatable, and early support makes a real difference. A primary care provider is a good first step. In the U.S., the National Alliance for Eating Disorders offers a free helpline at 1-866-662-1235.
The bottom line
Intermittent fasting is common among teens and young adults, and this study found it was linked to eating disorder attitudes and behaviors. For young people especially, steady, balanced eating is a safer foundation than strict fasting rules.
This article is for general information and isn’t medical advice. Talk with your healthcare provider about your individual needs.
