Barely a week goes by without someone is asking me about intermittent fasting. Some come in having already started it, often after watching a YouTube video or reading about it on Instagram. Some come with a printout of a study they found online. Some come confused because their neighbour lost eight kilos doing it and they tried it for two weeks and felt terrible.
I am going to give you the honest version. Not the version designed to sell you something, and not the version that dismisses it entirely. After two decades of clinical practice and years of watching the research evolve, here is what I actually think about intermittent fasting.
First, What Is Intermittent Fasting Actually?
Intermittent fasting, or IF, is not a diet in the traditional sense. It does not tell you what to eat. It tells you when to eat. It is an umbrella term for several different eating patterns that cycle between periods of eating and periods of fasting.
The most commonly practiced approach is the 16:8 method, where you eat within an 8-hour window and fast for the remaining 16 hours of the day. For most people this simply means skipping breakfast and eating between noon and 8 PM, or eating breakfast and an early dinner and not eating after 6 PM.
There is also the 5:2 method, where you eat normally five days a week and restrict calories significantly on two non-consecutive days. And there is alternate day fasting, where you alternate between regular eating days and very low-calorie days. These are more demanding and far less commonly sustained in real life.
What the Research Actually Shows
Let me be straightforward here because the science on intermittent fasting is genuinely interesting but also frequently misrepresented online.
The evidence shows that IF can be an effective strategy for weight loss and for improving certain metabolic markers like fasting blood glucose, insulin sensitivity, and triglycerides. Several well conducted trials have found meaningful improvements in these areas over periods of 8 to 24 weeks.
However, and this is the part that usually gets left out of the social media version, most rigorous studies show that the benefits of IF are broadly comparable to those of simple calorie restriction when total calorie intake is matched. In other words, IF works largely because people end up eating less overall, not because of any unique metabolic magic triggered by the fasting window itself.
There is some promising early research on time restricted eating and its effects on circadian rhythm, inflammation, and gut health. These are genuinely interesting areas. But the honest answer is that most of this work is still in early stages, conducted in small groups or in animal models, and we cannot yet make sweeping claims based on it.
Who Might Actually Benefit from It
In my clinical experience, intermittent fasting works well for a specific type of person. It is not for everyone, but when there is a good fit, it can be a genuinely useful tool.
People who are not breakfast hungry. A significant number of people eat breakfast not because they are hungry but because they have been told they must. If you genuinely have no appetite in the morning and feel fine delaying your first meal by a few hours, a 16:8 window may simply formalise what your body was already asking for.
People who struggle with portion control throughout the day. Having a defined eating window gives some people a clear, simple structure that works better for them than trying to track every meal and snack. It reduces decision fatigue.
People with insulin resistance or prediabetes who are not on medication. The evidence for improved insulin sensitivity with time restricted eating is reasonably consistent, and for this group it can be a valuable part of a broader lifestyle intervention.
People who want a sustainable, simple approach without calorie counting. For some, restricting the eating window feels less effortful than tracking every gram of food. Sustainability matters more than theoretical perfection, and if IF helps someone eat better long term, that has real value.
Who Should Absolutely Not Do It
This section is as important as everything that came before it, and I wish it appeared more prominently in the enthusiastic blog posts and reels that promote IF without qualification.
People with Type 1 or Type 2 diabetes on insulin or sulphonylureas. Fasting with these medications carries a real risk of hypoglycaemia, which is a serious and potentially dangerous drop in blood sugar. Please do not attempt any fasting protocol without explicit guidance from your doctor and dietitian.
Pregnant and breastfeeding women. Nutritional needs are significantly elevated during these stages and any form of fasting or restriction is inappropriate and potentially harmful to both mother and child.
Anyone with a history of eating disorders. Structured fasting protocols can reactivate restrictive thinking patterns and disordered relationships with food. This is not a risk worth taking.
Children, teenagers, and older adults above 65. Growing bodies need consistent fuel. Older adults are at risk of muscle loss and nutritional deficiency with restricted eating windows. These groups need more nutrition, not less frequent access to it.
People with thyroid conditions, adrenal issues, or a history of chronic stress and poor sleep. Fasting is a physiological stressor. For people whose stress response systems are already taxed, prolonged fasting can worsen hormonal imbalances rather than improve them.
The Part Nobody Talks About: What You Eat Still Matters
This is possibly the most important thing I want you to take away from this blog. Intermittent fasting is not a free pass to eat whatever you want during your eating window.
I have seen patients who began 16:8, felt virtuous about their fasting hours, and then proceeded to eat two large meals of biryani, fried snacks, and mithai within their window and wondered why their weight and sugar levels were not improving. The fasting window does not neutralise poor food quality or excessive calories.
If you choose to try intermittent fasting, the eating window still needs to be filled with real, balanced food. Plenty of vegetables, adequate protein, whole grains, healthy fats, and enough water. Without that foundation, IF becomes another short-term experiment that delivers short term results and long-term disappointment.
My Honest Clinical Verdict
Intermittent fasting is a legitimate dietary strategy with genuine evidence behind it for specific outcomes in specific populations. It is not a miracle. It is not dangerous for most healthy adults. And it is not the only path to better metabolic health.
For the right person, with the right health profile, and with professional guidance, it can be a useful and sustainable tool. For the wrong person, tried without context and filled with the wrong foods, it is just another diet that will not last.
Before you start any version of intermittent fasting, have a conversation with a qualified dietitian or your doctor. Not because it is inherently risky, but because the best nutrition plan is always the one that is designed for your body, your health history, your lifestyle, and your goals. A one size fits all approach to something as individual as metabolism is always going to leave some people thriving and others wondering what went wrong.
The hype around IF is loud. The research is nuanced. And your body deserves the nuanced version.