What is intermittent fasting, and does it work?
Intermittent fasting changes when you eat, not what you eat. The common 16:8 method means eating in an 8-hour window and fasting for 16 hours. Trials show weight loss similar to ordinary calorie reduction, no better, no worse. It suits some people's routine; it is not safe for everyone.
The common methods
| Method | What it means | Note |
|---|---|---|
| 16:8 | Eat within 8 hours (for example 12 pm to 8 pm), fast 16 | Most popular; easy if you skip nashta |
| 14:10 | Eat within 10 hours | Gentler starting point |
| 5:2 | Normal eating 5 days, about 500 to 600 calories on 2 days | Hard to manage with family meals |
| Alternate day | Very low calories every other day | High drop-out rate; not advised without supervision |
What the trials found
In the TREAT trial, 16:8 produced only about 0.9 kg of weight loss over 12 weeks, little more than the control group, and some of that was lean mass. A larger 2022 trial in China found that calorie restriction with or without a time window gave the same result after a year. The honest summary: the eating window helps some people eat less, and that is where the benefit comes from.
Making it work in a Pakistani routine
- A common window is 12 pm to 8 pm: skip nashta, eat lunch and dinner with the family.
- Do not use the window as permission to eat biryani, paratha and mithai; the calories still count.
- Keep protein high across both meals: eggs, daal, chicken, dahi.
- Drink water through the fasting hours; headaches are usually dehydration.
- If you get acidity on an empty stomach, this method may not suit you.
If you have diabetes, do not start fasting without your doctor; medicine timing and doses need adjusting, just as they do before Ramzan. See the Ramadan diet plan and the diabetic diet chart.
See a doctor first if
- You have diabetes, especially on insulin or sulfonylureas
- You are pregnant or breastfeeding
- You are underweight or have had an eating disorder
- You take medicines that must be taken with food
- You get dizzy, weak or faint while fasting
Common questions
What is intermittent fasting?
It is a pattern of when you eat, not what you eat. The common 16:8 method means eating within an 8-hour window and fasting for 16 hours, usually by skipping breakfast or finishing dinner early. It works for weight loss only if the eating window leaves you with fewer calories overall.
Is intermittent fasting better than a normal diet?
Trials comparing intermittent fasting with ordinary calorie reduction find similar weight loss over 6 to 12 months. It suits people who prefer fewer, larger meals and dislike counting; it does not suit people who get very hungry or who overeat after the fast.
How is it different from Ramzan fasting?
Ramzan fasting has no water from sehri to iftar, which 16:8 allows, and it shifts meals to the night. Many people gain weight in Ramzan because iftar is fried and heavy. The two are not the same, though the discipline of a fixed eating window is familiar in Pakistan.
Can I drink chai or coffee during the fasting hours?
Water, plain black tea, green tea and black coffee without sugar or milk are generally accepted. Anything with sugar, milk or calories ends the fast in practical terms.
Who should not do intermittent fasting?
People with type 1 diabetes or on insulin and sulfonylureas, pregnant or breastfeeding women, anyone under 18, people with a history of eating disorders, people who are underweight, and those on medicines that must be taken with food. Ask your doctor first if you have any long-term condition.
Will fasting cause muscle loss?
Not if you keep protein high (around 1.2 to 1.6 g per kg a day) and do some strength exercise. Long fasts with low protein and no exercise do cost muscle.
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Sources
- Lowe DA et al. Effects of time-restricted eating on weight loss and other metabolic parameters (TREAT randomized clinical trial). JAMA Intern Med, 2020
- Liu D et al. Calorie restriction with or without time-restricted eating in weight loss. N Engl J Med, 2022
- American Diabetes Association. Standards of Care in Diabetes, Section 5: nutrition therapy
- Hassanein M et al. IDF-DAR Practical Guidelines on diabetes and Ramadan, 2021