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Dietary Fats

The Foe? Good Fats vs Trans Fats And Why Your Body Needs Them

Quick Summary

Dietary fats are not the enemy that every influencer or ‘expert’ on social media is trying to convince you of. Fats might be a cause for concern, especially if you are concerned about your cholesterol levels, but even then, the body needs fat, and for good reason. Fats are an important macronutrient that fuel energy, build every cell membrane in the body, and help absorb certain vitamins, and the real question is not whether to eat fat but which kind and how much.

Deep Dive

Alongside protein and carbohydrates, fats are the most energy-dense of the three macronutrients, providing roughly 9 kilocalories per gram compared to 4 kilocalories from protein or carbohydrates, as per the ICMR-National Institute of Nutrition. Beyond energy, fat performs jobs no other nutrient can. It forms the structural wall of every cell, cushions organs, insulates the body against cold, and acts as the transporter for fat-soluble vitamins A, D, E and K, which cannot be absorbed on their own. 

Fat also supplies linoleic and alpha-linolenic acid, which are two essential fatty acids the body cannot produce and therefore must get from food sources, and these in turn are used to build hormones and support brain and nerve function, as documented in a review published in the American Heart Association's journal Circulation. In short, when it comes to moderating fat, focus on good sources, especially if you are trying to follow a low-fat diet, because the body needs fat.

The Good, The Bad and the In-Between of Dietary Fat

There are different sources of dietary fat, and not all of them are processed the same way once they enter the body. Understanding the main types of fats is the first step to eating smarter rather than eating less or cutting them out completely. Broadly, food fats fall into three categories, and each one interacts with cholesterol and heart health differently, per Harvard's Nutrition Source:

• Saturated fats are solid at room temperature and can be found in ghee, butter, red meat, full-fat dairy, and coconut and palm oil. It raises LDL, the ‘bad’ cholesterol, when consumed in excess.

• Unsaturated fats are liquid at room temperature and include monounsaturated fat (olive oil, mustard oil, peanuts, avocado) and polyunsaturated fat (sunflower oil, walnuts, flaxseed, fatty fish like salmon, hilsa, anchovies). This is the category nutrition experts consider the healthiest.

• Trans fats are formed when liquid oils are industrially hydrogenated into a solid form. These can be found in vanaspati, margarine, bakery shortenings, and many fried or packaged snacks. It offers no nutritional benefit and is harmful to heart health.

Most whole foods contain a mix of these, so the goal is not to hunt for a single ‘perfect’ fat but to shift the overall balance toward the unsaturated end of the spectrum.

What is Trans Fat and Why is it the ‘Bad’ Fat?

Among all dietary fats, trans fat earns the worst reputation because of how it behaves in the bloodstream: it simultaneously raises LDL cholesterol and lowers HDL, the ‘good’ cholesterol that helps clear arteries, a double effect that saturated fat alone does not produce. The World Health Organisation has stated that no safe threshold of industrially produced trans fat has ever been established, which is why its global guidance calls for keeping trans fat intake below 1% of total energy. 

India carries a particularly heavy burden here, as the Food Safety and Standards Authority of India (FSSAI) has pointed to the country's high rate of trans-fat-linked heart disease deaths as the reason it has capped industrial trans fat at 2% of the total oils and fats used in any food product, a rule in force since January 2022. Vanaspati-based sweets, samosas, bakery items and reused frying oil remain the most common everyday sources in Indian kitchens and street food.

Good Fats vs Trans Fats

Here’s reiterating that your body needs fats—the good kind—and they shouldn’t be completely eliminated, as the mass consensus was at a certain point. So an overview of the good fats and bad fats, which are trans fats, might help.

Completely Eliminating Fat From Your Diet Can Backfire

For several decades, the advice was to cut out dietary fats, a medical recommendation and not just a social media fluke, for most countries, and it did not deliver the results it promised. A review published in 2016 at the Harvard T.H. Chan School of Public Health called the low-fat era a failed experiment. The same news piece observed obesity and type 2 diabetes rates climbing even as fat intake fell, because refined carbohydrates filled the gap fat left behind. 

Cutting fat aggressively carries direct physiological costs, since vitamins A, D, E and K need fat to be absorbed; a very low-fat diet can lead to deficiencies in all four, and inadequate intake of the essential fatty acids found only in food has been linked to impaired immune function and hormonal disruption in clinical literature published in The American Heart Association’s journal. Skin that turns dry and dull, brittle hair, and unusually low energy are often early, easy-to-miss signs that a diet has strayed too far away from good fats rather than just away from the bad fats.

Does Eating Fat Actually Cause Weight Gain?

A Harvard analysis of 53 randomised trials involving roughly 68,000 people, published in The Lancet Diabetes & Endocrinology, found that low-fat diets provided no meaningful long-term weight-loss advantage over higher-fat diets; both groups lost and maintained about the same amount of weight over a year or more. Separately, the large multi-country PURE study in The Lancet found that higher total fat intake was associated with a lower risk of death, while very high carbohydrate intake was linked to a higher one. None of this means fat gets a free pass, as a gram of fat still carries more than double the calories of a gram of carbohydrate or protein, so portion size is important. But the evidence here is consistent: total calorie balance, food quality and physical activity influence weight far more than the presence of fat on a plate.

How to Choose Healthy Fat Sources in Everyday Cooking

Building a diet with the right balance of dietary fats does not require giving anything up outright; it mostly means shifting proportions. A few habits make it easy to favour the right types of fats without much effort:

• Cook with mustard, groundnut or olive oil most days, and reserve ghee or butter for occasional use rather than every meal.

• Snack on nuts and seeds like almonds, walnuts, flaxseed, chia instead of packaged namkeen or bakery items made with vanaspati.

• Include fatty fish, such as rohu, hilsa, mackerel, sardines, or salmon, once or twice a week for omega-3s.

• Read ingredient labels for the words ‘partially hydrogenated’ or ‘vanaspati’, both signals of trans fat.

• Avoid reusing frying oil multiple times, since repeated heating raises harmful compounds in the oil.

None of these good sources of fat needs to be expensive or exotic, as many are already part of everyday Indian cooking, and the shift is really about frequency and proportion of healthy fat sources added to your diet, if you are aiming for a low-fat diet, rather than an overhaul of having a fat-free diet.