WHY are they not suitable for doing IF?
1. People with eating disorders
This group should have a regular eating behaviour, therefore it is not a wise choice to enforce a weight loss plan.
2. People with diabetes
Stabilising blood sugar levels (BSL) is the first priority for people living with diabetes. Fasting reduces both insulin and BSL which may pose risk to patients, especially type 1 diabetes who need insulin injection regularly.
3. Pregnant/ breastfeeding women
Calorie restriction is not recommended during pregnancy/ breastfeeding as it might affect baby’s development. Energy intake is required for providing nutrients to foetus and/or milk production.
4. The elderly
This group requires more calorie intake for maintaining energy and muscle.
5. People who are underweight
IF is used for weight loss which is not designed for underweight people. A calorie surplus is needed for them but not a calorie deficit.
6. People with sleeping problems
A good sleep assists with supporting brain functions and emotions. A restrctive diet may pose a further burden to this group of people, such as bad mood, lack of energy.
7. People who are physically active
We need additional carbs and protein intake before and after exercise for muscle building and repair. It is not ideal to skip a post-exercise meal if it does not fit into the IF fasting window.
8. People with gut issues
People normally eating 2 large meals during IF instead of 3 meals. Large meals may cause stress on our stomach & gut, leads to worsening symptoms e.g. bloating and indigestion etc.
Should I do intermittent fasting for weight loss?
The theory behind intermittent fasting is reducing intake due to a long fasting hours. People typically reduce consumption due to the time restriction. Therefore, a “normal” balanced diet with a calorie deficit will do this favour as well. There is no one size fits all. IF may be effective for some people but may not for you. I recommend following a diet that you can stick with for long term, it would definitely be the most appropriate diet for you!
Limitations of recent studies
Although there are studies related to the effectiveness of intermittent fasting, most of the intervention are animal studies which may not be accurate if applying to humans (based on what I have read from the previous post). Even if some studies involved humans, the intervention period is very short, usually within 3-12 weeks .
 Patterson RE, Laughlin GA, LaCroix AZ, Hartman SJ, Natarajan L, Senger CM, Martínez ME, Villaseñor A, Sears DD, Marinac CR, Gallo LC. Intermittent fasting and human metabolic health. Journal of the Academy of Nutrition and Dietetics. 2015 Aug 1;115(8):1203-12.