By Leah Blalock, clinical dietitian at CHOC
Over the years you’ve heard different forms of fasting, including intermittent fasting, promoted for weight management and disease prevention, but do these techniques work and are they safe for children? Studies have shown that reducing typical calorie consumption, usually by 30-40 percent, extends the lifespan by a third or more in many animals. When it comes to calorie restriction in humans, however, the jury is still out. Even if calorie restriction does not help anyone live longer, a large portion of research has supported the idea that limiting food intake reduces the risk of diseases common in old age and lengthens the period of life spent in good health.
Intermittent fasting (IF) may be an alternative to traditional dieting for adults but has not been studied in children. However, research results on benefits of intermittent fasting has not been consistent. While some studies have shown potential benefit, others have shown no difference with regards to weight loss/weight maintenance, blood sugar control, and blood lipids.
Three methods of intermittent fasting
Research does suggest that the timing of the fast is key. There are three kinds of intermittent fasting, all of which involve splitting the day or week into eating and fasting periods. The 16/8 method or time splitting method, involves skipping breakfast and restricting daily eating period to 8 hours, (such as from 1 p.m. to 9 p.m.). Then there is then a 16 hour fast in between. The Eat-Stop-Eat or “alternate day” method involves fasting for 24 hours, once or twice a week. The 5:2 method allows 20-25 percent of estimated caloric needs on fasting days and unrestricted intake on non-fasting days.
How effective is intermittent fasting?
One trial which involved randomly assigning participants into alternate day fasting, caloric restriction, and control groups showed the alternate day fasting group had a high dropout rate. There was no significant difference in weight loss, blood pressure, heart rate, triglycerides, fasting glucose, fasting insulin, and insulin resistance between the fasting and restriction group. In addition, The LDL cholesterol (“bad” cholesterol) rose significantly in the fasting group compared to the restriction group.
A recent study involving adults with type 2 diabetes compared the 5:2 diet to caloric restriction and found that both interventions had similar improvements in hemoglobin A1C (a marker of blood sugar control), fasting glucose (blood sugar) levels, and lipid levels. The safety of intermittent fasting for a person with diabetes depends on their medications and risk for hypoglycemia.
Intermittent fasting does not appear to offer superior metabolic or short-term weight control advantages compared to caloric restriction. However, some people may find intermittent fasting easier to maintain. Those with a history of disordered eating should not attempt any sort of fasting diet. When restricting food, there is an increased release of dopamine in the brain when you do eat. This could increase the likelihood of a binge.
Recent studies continue to show that despite similar calorie intake, physical activity, and sleep, those who skipped breakfast more frequently had higher body mass than those who eat earlier. High caloric intake at breakfast instead of dinner has also been associated with improved weight loss/weight maintenance. Skipping breakfast for children is not recommended because they have already fasted overnight.
Research studies suggest that circadian rhythm fasting combined with a healthy diet and lifestyle can be an effective approach to weight loss. Research also supports adequate sleep as a tool for health (which consists of an overnight fast of 8-12 hours). Improving sleep quality and quantity may improve metabolic health. It is important to focus not just on what we eat, but also when we eat. Limiting food intake in the evening and at night may have beneficial effects on glucose control and energy balance.
Is intermittent fasting safe for kids?
There is not enough evidence in humans to recommend IF at this time. There have been no studies in children and, current studies in adults lack long-term intervention and follow up period.
Intermittent fasting is not recommended for those in periods of rapid growth, such as children and adolescents. IF is also not recommended for people with diabetes on medication, people with a history of eating disorders, and pregnant or breastfeeding women.
An intentional approach to eating is recommended for children and adolescents. Follow these tips for helping your child manage a healthy weight:
- Use planned meals and snacks timed throughout the day to help manage hunger and achieve portion control.
- Minimize or eliminate sugary beverages.
- Consume nutrient dense foods including at least five servings of fruits and vegetables daily.
- Cut back on processed and fast foods.
- Mindful eating is also key to promoting a healthy relationship with food. Mindful eating is eating with intention and attention.
- Take the time to eat at the table as a family.
Let’s not forget the importance of activity. Exercise is a vital component of any child’s development. It helps to reduce overweight and obesity, increases strength in muscles and can improve concentration at school. Limit screen time and encourage outside play. Families can exercise together to meet the recommended 60 minutes per day.