Cooking fat is easy to leave out of a food diary because it disappears into the dish. You do not need to measure it. Write how the food was cooked and what fat went in, with a rough amount in your own words: “chicken thighs, roasted in olive oil, a good glug” or “eggs fried in butter, a little”. That is enough to tell a lightly cooked meal from a richly cooked one when you look back.
This guide is about the fat you use when you cook at home. Fat added at the table, such as dressing or butter on bread, is covered in the guide to sauces, condiments and side vegetables. Foods you did not cook yourself are a different problem, because you often cannot know what went in.
Why cooking fat is worth a few words
Two plates of the same ingredients can differ a lot depending on how they were cooked. Boiled potatoes and roast potatoes are the same vegetable in a different form. A diary that only says “potatoes” hides that difference, and a hidden difference can later look like a mystery.
There is also some evidence that fat is a plausible thing to keep an eye on, though it is narrower than it might sound:
- A 2016 narrative review of dietary fat and functional dyspepsia (long-lasting indigestion with no clear structural cause) summarised laboratory studies in which adding fat to a meal produced more fullness, bloating and nausea in people with dyspepsia. The authors described the evidence as limited and called for larger studies.
- A 2020 review of diet in functional dyspepsia reported that, in a randomised study, low-fat foods that patients believed were high in fat triggered symptoms similar to genuinely high-fat foods. It also noted that the effect of changing diet on symptoms had not been tested in randomised prospective studies.
Both reviews concern people with functional dyspepsia, not everyone with bloating, and neither shows that fat is the reason for your symptoms. The NHS page on indigestion lists fatty or spicy foods among things that can bring indigestion on, which is a general statement rather than a finding about you. The practical point is modest: if fat does matter for you, a diary with no record of it cannot show that, and if it does not, a diary that includes it can show that too.
What to write: method, fat, rough amount
A hospital diary from Leeds Teaching Hospitals NHS Trust asks readers to write the method of cooking, for example grilled, fried or baked, and its sample entries mention margarine and butter in plain terms. Three short pieces are enough:
- Method: fried, roasted, grilled, baked, boiled, steamed, stir-fried, air-fried.
- Fat used, if any: “olive oil”, “butter”, “ghee”, “lard”, “no added fat”, or “spray oil”. If you do not remember the type, “cooking oil” is better than nothing.
- Rough amount: “none”, “a little”, “a tablespoon-ish”, “a generous splash”, “shallow-fried in about 1 cm”.
Examples:
- “Sunday roast: beef, roast potatoes in vegetable oil (plenty), boiled carrots.”
- “Stir-fry with a little sesame oil, no other added fat.”
- “Pasta, then sauce made with butter and cream, quite rich.”
Compare these with a bare “roast potatoes”. The extra words take seconds.
Use your own scale, and keep it steady
Pick a few words and use them the same way each time. “A little”, “normal” and “a lot” are enough. What matters is that the words mean roughly the same thing across weeks, not that they match a measuring spoon. If you already use words for symptom severity, the same habit applies: consistency beats precision.
If you do happen to measure, because you follow a recipe, write the measure down. Do not start measuring just for the diary. Weighing food tends to turn a light-touch habit into a chore, and chores are what get dropped.
When you do not know what was used
Often you will not know the fat. Takeaways, restaurant meals, canteen food and meals cooked by someone else rarely say. Write what you know and mark what you do not:
- “Takeaway curry, oil or ghee unknown, looked rich.”
- “Fried breakfast at a café, fat unknown.”
“Looked rich” is an impression, not a measurement, so keep it clearly as your note. The guide to recording a mixed meal uses the same approach for unknown ingredients: recording “unknown” is honest and stops a later comparison from looking more certain than it was.
Do not overfill the page
A diary that records everything about cooking fat can become heavy. Some limits help:
- Record the fat only when you added a noticeable amount or cooked it in a clearly different way from usual. “Same as usual” is a valid entry once you have written down what usual is.
- Do not label foods “high-fat” or “low-fat” in the diary. A label is a judgement. The method and fat you used are observations.
- Do not let the diary make you wary of cooking with oil or butter. Fats are an ordinary part of most diets, and this note exists to preserve information, not to rate your food.
One caution on honesty: research on dietary records has suggested that people tend to under-report foods they think of as unhealthy. A review of under-reporting in dietary surveys concluded that fat is likely to be under-reported, but the authors presented this as a logical inference rather than a direct measurement. That research concerned dietary surveys rather than symptom diaries, but it is a reminder to write down the butter you would rather not mention. The diary is for you, and a flattering record is less useful than an accurate one.
What a note about fat cannot tell you
A line saying “fried in butter” followed by bloating is an observation, not a cause. Rich meals are often larger, eaten later or eaten at restaurants, and they may come with other ingredients, alcohol or a stressful evening. The guide to telling which meal caused bloating explains why one sequence does not identify a trigger and why repeated, comparable entries matter more.
Avoid two moves that this kind of note invites. One is writing fat in the diary only on bad days, which makes it look more important than it is. The other is cutting out oil, butter or fried food entirely because of what you see. If you are thinking about restricting what you eat, talk to a doctor or dietitian first; restriction can narrow your diet and may not help.
When to get advice
Persistent indigestion or bloating is worth discussing with a professional rather than managing alone. The NHS advises seeing a GP if bloating happens regularly, or you have tried changing your diet and still feel bloated, and says to seek urgent advice if bloating comes with symptoms such as vomiting, a fever, or a swelling or lump in your tummy. The NHS also advises seeing a GP if bloating comes with unintentional weight loss or blood in your poo. A diary can make that conversation clearer, but it does not replace it. This article was not professionally reviewed.
If you would like a lower-effort way to keep preparation details alongside meals and symptoms, you can get GutBloom on Google Play.
Sources
- Advanced Biomedical Research (2016) — Dietary fat intake and functional dyspepsia
- Frontiers in Psychiatry (2020) — The Role of Diet in Functional Dyspepsia Management
- Nutrition Research Reviews (1998) — Assessing dietary intake: Who, what and why of under-reporting
- Leeds Teaching Hospitals NHS Trust — Your enzyme and food diary
- NHS — Indigestion
- NHS — Bloating