A working reference · September 2026
Thirty-six things people repeat about Indian food. Every one of them held against a published source, with the source printed underneath so you can go and look for yourself.
None of this is my opinion. Where I could not find a real source, the line was cut, however good it sounded.
The numbers are printed. If a figure could not be traced back to a measurement, it is not on the page.
Half true is the interesting column. Most kitchen advice is a true thing that grew in the retelling.
This is general information. It is not medical advice and it is not a plan for your body. Full note at the end.
More fear lives in the Indian cookware cupboard than anywhere else in the house. Most of it is misplaced, and the one real risk gets almost no attention.
This is not folklore. Iron moves from the pan into the food, and it shows up in blood tests. Acidic, watery, long cooked things like tomato, tamarind and sambar pull the most.
What it is not: a treatment for anaemia. The size of the effect swings with how consistently the pot is used, and with infections like malaria and hookworm. Use the kadhai. Also get the blood test.
Source: systematic review, PubMed 34290890 and 31479458
The American Cancer Society's position is that there are no proven risks to humans from cooking on non-stick coatings. A scratched pan is not a health event either. The flakes pass straight through.
The one real rule: never heat an empty non-stick pan on a high flame. That is the only way a home kitchen reaches the temperature where the coating breaks down. A pan with food or oil in it does not get there.
Source: American Cancer Society
This one has been passed around Indian kitchens for thirty years. It was investigated properly and no link was found between cookware and Alzheimer's disease.
The claim that is supported is narrow and specific, cookware and Alzheimer's, and I am not stretching it into "aluminium is harmless everywhere". It answers the question people actually ask.
Source: Alzheimer's Research UK and CCOHS
Clay is having a revival and is assumed to be the innocent choice. The risk is not the clay, it is the glaze. Lead containing glazes fired at the wrong temperature can leach into food, especially with anything acidic.
The US regulator names the pattern to avoid: handmade, crude or irregular, antique, damaged, or bought from a street vendor or a flea market. Factory cookware sold as food safe is tested for exactly this. So buy the tested one, and enjoy it.
It does not. A cooker is shorter and uses less water than an open boil, and those two things are what protect a vitamin. Against boiling, the cooker generally comes out ahead.
Where it is not a clean win: results vary by vegetable and by vitamin, and one Indian study found pressure cooking caused the largest iodine loss of the methods tested. So the honest claim is "not worse than boiling", not "best at everything".
Source: PMC3791240 and PMC10660054
Almost every kitchen loss comes down to one rule that nobody is taught. The more water something sits in, the more of it leaves the food.
Boil a vegetable and pour the water down the sink, and a real part of the vitamin C goes with it. Keep the water. Into the dal, into the gravy, into the atta.
I am not going to give you a percentage. Reported losses run from roughly 15% to over half, depending on the vegetable and how long it sat there. The direction is solid, the single number is not.
Source: PMC8791706 and Food Science and Biotechnology, 2018
It is the most feared appliance in an Indian kitchen and it should not be. A microwave keeps more vitamin C in a vegetable than boiling does, because it uses almost no water and takes almost no time.
Not a blanket win. The same study found microwaving lost the most vitamin K in some greens. The rule that survives is about the water, not about the machine.
Nobody thinks salt can lose anything. It can. A large part of the iodine goes during cooking, and the fix costs nothing. Add the salt at the end, not at the start.
This is not an argument against iodised salt. It is an argument for it, used better. Storage barely matters: over 80% is retained in any normal container.
Source: PMC3791240 and Food Chemistry
Raw is assumed to be the more nutritious form of everything. For the lycopene in a tomato it is the other way round. Heat plus a little fat makes it far easier for the body to use. Your everyday tomato and onion base is doing this already.
This does not generalise. Cooking helps carotenoids and hurts vitamin C, so "cooked is healthier" is not a rule and I will not write it as one.
Source: PubMed 11982434 and British Journal of Nutrition, 17391568
Oil goes bad long before it looks bad. Strain it, hold it up to the light, and it tells you nothing. The measure that matters is a laboratory one, how much of the oil has turned into polar compounds, and India has a legal ceiling for it.
There is no honest "reuse it twice" number, and anyone who gives you one has made it up. At home: fry, use it again once soon after for something similar, and stop when it darkens, thickens, smells sharp or foams.
Everybody repeats this, and the reasoning behind it, smoke point, turns out to be a poor guide to how an oil actually holds up in heat. Extra virgin olive oil produced fewer harmful compounds when heated than several refined seed oils with higher smoke points.
What this does not say is that olive oil is the best oil for a tadka. Mustard and groundnut oil were not in that comparison, so there is no ranking here. It only kills the reason people give.
The three things in almost every Indian meal, and the three places where a small change of habit is worth more than any supplement.
Cook rice, chill it overnight, reheat it the next day, and it raises blood sugar less than the same rice fresh. Chilling turns some of the starch into a form your body does not absorb. Leftover rice is the better option, not the worse one.
It is a real effect and a small one. This is not a treatment for diabetes, and I am not putting a percentage on it. Read it together with the next entry, because the rice has to go into the fridge quickly.
Source: PubMed 26693746
The whole country blames the reheating. It is the sitting out that does it. Uncooked rice carries spores that survive cooking. Left at room temperature they grow and make a toxin, and reheating does not destroy that toxin.
So the rule is about speed, not about the microwave. Cool it fast, fridge it, keep it a day, reheat once until it is steaming through.
Source: UK Food Standards Agency
It is doing something you were never told about. Rinsing takes some of the arsenic out. Cooking rice in a lot of water and draining it takes out considerably more.
And there is a cost to draining that matters in India now. It washes out the added vitamins in fortified rice, which is what comes through the public distribution system. Rice is not dangerous. Rinse it, and think twice before draining fortified rice.
Source: Royal Society of Chemistry and PubMed 26515534
It reduces it. The sugars that cause the gas drop by roughly a quarter, not to zero. And the whole thing only works if you throw the soaking water away, which is the half everybody skips.
Soaking and then cooking in the same water achieves close to nothing. Fresh water, every time.
Source: Journal of Nutritional Science and Vitaminology, 2002
They are two different legal categories in India. Brown bread only has to be half whole grain flour. The rest can be maida. Whole wheat bread has to be three quarters.
The colour is not quite the trick people think it is. The honest fight here is the 50%, not the caramel. Turn the packet over and read the category, not the front of the bag.
Three products sold on a health story. All three stories are weaker than the price tag suggests.
Brown sugar does carry traces of calcium, potassium, magnesium and iron from the molasses. A tablespoon supplies under one percent of a day's need of any of them. That changes nothing about anything.
It is the same sugar with a story attached. If you prefer the taste, use it for the taste.
Source: EUFIC
It is not the gentler option. Jaggery raises blood sugar at least as much as white sugar does. Diabetics and people trying to lose weight switch to gur believing they have solved something, and they have not.
I am not giving you a glycaemic index number, because the Indian study that reported one is from 1987 and small, and different jaggeries behave differently. And gur does carry iron and minerals that white sugar does not. That is true, and it is a separate point from blood sugar.
Source: RSSDI, 1987 and review, 2022
About 8% less, which the researchers who measured it called clinically irrelevant. If you are watching sodium, sendha namak does not help you.
The difference that does matter runs the other way. Table salt is iodised and rock salt is not. In a country with a real iodine problem, quietly replacing all your salt with pink salt is a downgrade, not an upgrade.
Source: laboratory analysis, PMC7603209
The things done every morning without question. Some are worth keeping for reasons other than the one you were given. Some are not doing anything at all.
Every Indian household does this believing something is released. Soaking makes the skin come off. It does not get you more out of the almond. Soaking chopped almonds actually lowered the mineral content, because the minerals leached into the water.
Keep doing it if you like it. Soaked almonds are easier to chew and less bitter, and for a child or an older person that is a real reason. It is just not a nutrition reason.
Source: Food Chemistry, 2020
You do not get all of them. The cell walls of a whole almond keep some of the fat from ever being absorbed, so the label overstates what reaches you. People trying to lose weight cut out nuts on a number that is not the real one.
Grind them and the gap closes. This does not carry over to almond flour or almond butter, where the label is closer to the truth.
Source: USDA and American Journal of Clinical Nutrition
Black pepper does make turmeric substantially easier for the body to absorb, and adding it costs you nothing. That part is worth doing.
The famous "2000%" figure comes from a single 1998 study with a small number of volunteers and has never been independently replicated. I will not put that number on anything, and neither should anyone selling you a supplement with it on the label.
Both sides of this argument are wrong, so here is the measured half. Water left overnight in a copper vessel is well inside the safety limit for drinking water. It is not poisoning anyone.
And it is not treating anything either. Detox, digestion, weight loss, none of that is sourced, so none of it is here. Hot water pulls far more copper than cold, and water standing for days pushes the level up. Overnight and cold is fine.
The single most repeated Indian weight loss ritual, and the trials behind it did not test it. They used three grams of cumin powder swallowed every day, not a glass of jeera water, and most of them ran alongside diet counselling, which is very likely what was doing the work.
One thing did survive. A 2025 pooled analysis found a real effect on fasting blood sugar. That is a different claim from weight, and it deserves to be stated as its own.
Source: meta-analysis, PMC12834730
About five times. The measured figures are right there in India's own food composition tables. Even the older, higher amla number that still circulates would only get you to about eleven times. Nothing supports twenty.
Five times is still excellent, and amla is still one of the best things in an Indian winter. It did not need the exaggeration. I have repeated the twenty times line myself in the past, which is exactly why it is on this page.
Source: ICMR-NIN, Indian Food Composition Tables 2017 and USDA
An extremely widespread warning with nothing behind it. Heating honey does form a compound called HMF, and reviews have not demonstrated harm to people at the amounts found in food. Your coffee contains considerably more of it than your honey does.
What heating genuinely does is destroy honey's enzymes, which is why HMF is used as a test of whether honey has been overheated or is old. A quality question, not a safety one.
Source: BMC Chemistry, 2018 and EFSA, 2022
This is the one entry on the page where I cannot give you an answer, and I would rather say so than pick a side. Mustard oil is banned for cooking in America and completely legal in India, and the human evidence has never settled it.
The American ban rests on rat studies from over forty years ago using very high levels of erucic acid. No human study has shown the same at normal intakes, and a 2021 review called the effects in humans unclear and asked for the ban to be reviewed. Both camps are certain. Neither has the evidence.
One of the most firmly held rules in Indian homes, and there is nothing under it. The stomach produces acid as it needs it, so there is no reservoir sitting there waiting to be watered down.
I am not going the other way and telling you that water with meals aids digestion or helps you lose weight, because that is not sourced either. And if you have reflux, a lot of liquid at a meal may genuinely feel worse. Drink when you are thirsty.
Source: Nutrients, "Water at Meals"
The last eight are not about ingredients at all. In my practice they change more than any swap on the list above.
Ragi has about three times the calcium of milk, gram for gram. For anyone who does not drink milk, or cannot, that is a genuinely useful thing to know and almost nobody is told it.
Not a straight swap, though. Dairy calcium is absorbed better, and one review put calcium retention from a finger millet diet at about 23%. Ragi is a real calcium source. It is not a replacement for milk.
Cook dahi and the live bacteria die. The international food standard drops the live culture requirement entirely for fermented milk that is heat treated afterwards, which is the plain admission that heating removes them.
This is not an argument against kadhi. The protein and the calcium go nowhere, and it is a good meal. Just do not eat it for your gut. For that, the dahi has to be cold.
Source: Codex CXS 243-2003, section 2.1
Kept cold, cut fruit looks bad long before it loses anything worth counting. This one matters for real life, because it means fruit cut in the morning and eaten from the fridge in the evening is still fruit.
The study ran at 5 degrees, in the fridge. None of this applies to a plate of cut fruit sitting out on the counter or in a tiffin all afternoon.
The signal that you have had enough reaches the brain roughly twenty minutes after you start eating. Which means that for the whole of a fast meal, you are eating without the information.
This is the single most useful line on this page. It is why the second helping should wait, and why nothing else on this list will do as much for you.
Source: reported research summary
It gives you the chance to notice fullness while there is still food on the plate. That is real and it is worth doing.
But I have to be straight about who it was shown in. In a randomised crossover study the effect on how much was eaten was significant in normal weight people and not in people who were overweight or obese. About half the people I work with are trying to lose weight, so I will not sell them a result that was not found in them.
Source: American Journal of Clinical Nutrition and PubMed 24215801
Falling asleep is not the measure. Evening screen light pushes the body clock back by up to about an hour and a half, so you sleep at the same time and your body is running on a different one.
I am not claiming it causes insomnia. The shift in the clock is what was measured, and it is enough to matter for how you eat the next day.
Source: PNAS
It changes how tired you feel, not how tired you are. Caffeine blocks the signal that tells you about the tiredness. The tiredness itself is still there, waiting, unaffected.
I am not going to tell you the crash is worse than where you started, because that question is not settled and the point does not need it. Coffee is fine. Just do not use it to answer a sleep problem.
Source: Journal of Sleep Research
No single food causes weight gain. The count does. One medium banana is about 105 calories, which is a snack, not a problem.
This is a point about portions and I am not going to dress it up as a finding. What I see in practice is people cutting fruit out entirely while trying to lose weight, and losing something they actually needed.
Source: USDA food data, medium banana
Everything above, reduced to what actually happens in a kitchen between seven and nine in the evening.
I kept seeing the same lines repeated with total confidence, including by me. The twenty times amla line is one I have said out loud more than once. When I finally went and looked, it was five.
So I went through everything I say most often and checked it properly. Four of the claims I had already published turned out to be wrong or overstated. Those corrections are on this page, in the same type as everything else.
If you disagree with an entry, the source is printed under it. Go and read it. That is the entire point of the format.
This page is general information about food. It is not medical advice. It is not a diagnosis, not a treatment, not a prescription and not a nutrition plan. Reading it does not make you my client and does not create a nutritionist and client relationship between us.
Do not use it to treat or manage a health condition, and do not use it to change or stop any medicine. If you are pregnant or breastfeeding, if you are under eighteen, if you take regular medication, or if you have a condition such as diabetes, thyroid disease, kidney disease, heart disease, an allergy or a digestive disorder, speak to your doctor or a qualified professional before changing anything you eat. In an emergency, contact a doctor or your nearest hospital immediately.
Bodies differ. Every entry above describes what has been measured in research groups. It does not predict what will happen in you, and any of these lines may be wrong for your particular body.
The sources belong to the people who published them. They are listed so you can check my working. They are not endorsements of me, of this page or of my practice, and I do not control them or their content. Food science is revised over time and any entry here may be out of date by the time you read it.
You act on this at your own discretion. To the fullest extent permitted by law, Ruchi Gurnani accepts no liability for any loss, injury or damage arising from any use of, or reliance on, the information on this page.
Checked and published September 2026 · Ruchi Gurnani, Delhi NCR · ruchigurnani.com