Intermittent Fasting: Safety & Eligibility
What are the potential benefits of intermittent fasting?
Intermittent fasting can help with weight loss efforts, due to it being a calorie-reduction approach. Whilst research around intermittent fasting is still emerging, there are promising results suggesting it may benefit health by improving insulin sensitivity and blood sugar control, reducing blood pressure, and improving appetite hormone regulation, among other possible benefits. However, more long-term studies are needed to fully understand the role intermittent fasting may play in long-term health.
What are the potential negatives to intermittent fasting?
Intermittent fasting doesn’t suit everyone. There can be a number of side effects, including feelings of extreme hunger, dizziness, feeling faint, irritability, lethargy, reduced concentration, reduced exercise motivation or potential nutrient deficiencies. It’s important to listen to your body and aim to consume food if you feel unwell at any time. You must drink adequate amounts of fluid while fasting and avoid strenuous activity. To avoid risking nutrient deficiencies, it’s important to focus on eating adequate calories during your eating window, as well as prioritising nutrient-rich whole foods.
Should I try intermittent fasting?
It’s completely personal preference whether intermittent fasting is something you wish to try. It’s not necessary for weight loss, but it’s one method some people choose. Before making any significant changes to your dietary habits, it’s important to talk to your GP beforehand to ensure they feel it is safe to do so.
Who shouldn't do intermittent fasting?
There are certain groups of people for whom intermittent fasting is not appropriate. This includes the following:
- Pregnant or breastfeeding women
- Individuals with a history of disordered eating
- Individuals with type 1 diabetes (insulin-dependent)
- Individuals with a BMI below 18.5
- Individuals taking medications (consult your doctor)
- Children or adolescents
How frequently can I fast?
Depending on the fasting approach you are taking, some people choose to fast for periods of time every day (e.g. for 16 hours out of 24), while others may do it more infrequently. Ultimately it comes down to your main goal with fasting – if it is to support weight loss, then the most important factor is that you’re in a moderate calorie deficit over time. Look at your week as a whole using your 'Week View' to ensure you’re sticking to your calorie deficit on average, while also ensuring you’re not dropping too far below this and risking undereating.