Fats - friend or foe? Why the body needs fat (even if you learned to fear it)
For a long time, fat got blamed for almost everything. The "low-fat" message of the 1990s and 2000s was so loud and so consistent that many people still carry a quiet unease around foods like avocado, cheese, nuts or the skin on a chicken thigh - a sense that eating them is somehow careless, even when the rational part of the mind knows better.
That unease has a history and is the result of decades of public health messaging that treated fat as the direct cause of weight gain, when the reality was the science is far more nuanced than that.
Fat is one of three macronutrients the body relies on, alongside protein and carbohydrate, and it does jobs that nothing else in our diets can fully replace.
What dietary fats do for the body
It forms part of every cell membrane in the body, including in the brain and nervous system.
It's needed to absorb vitamins A, D, E and K from food - without enough fat in a meal, those vitamins largely pass through unused.
It plays a role in hormone production, including hormones involved in mood, metabolism and reproductive health.
It supports skin, hair and nail health, and helps keep joints comfortably cushioned.
It helps a meal feel satisfying, both by slowing how quickly food moves through the digestive system and through taste and texture.
Oily fish such as salmon, mackerel and sardines, along with foods like walnuts, chia and flaxseed, supply omega-3 fats specifically, which are linked to a steadier mood, immune function and joint comfort.
DIETARY FAT COMES IN VARIOUS FORMS
Fat isn't one single thing. Unsaturated fats - found in olive oil, avocados, nuts, seeds and oily fish - are usually liquid at room temperature. Saturated fats are usually solid at room temperature and occur naturally in foods like meat, dairy, coconut and palm oil. Trans fats are mostly created industrially, through a process that turns liquid oils into something more solid and shelf-stable for processed food - though there's now a legal limit on how much can be in anything sold at retail in the UK and most manufacturers moved away from it well before the law caught up.
None of these categories need tracking or comparing against each other. The research linking fat to health outcomes looks at patterns of eating over months and years, not at any single food or any single label. That's worth keeping in mind, because nutrition labels put a number on fat and saturates on every product.
Take a ready meal, for example - looking at the label, it may be easy to read that number as a verdict on whether the meal is an acceptable choice. In reality, it can’t dictate that alone - there will be a number of factors influencing how that meal serves you, both nutritionally and in terms of what's available and what appeals - and one meal is always part of a much wider pattern.
A note on "low-fat" and "fat-free" products
When fat is removed from a processed food, something usually has to replace it to keep the taste and texture acceptable - often sugar, salt, starches or sweeteners. That doesn't make a low-fat product the wrong choice. It simply means "low-fat" isn't automatically the more nourishing option. It is worth reading the label rather than assuming this.
A meal with no fat in it at all rarely feels satisfying for long and that lack of satisfaction often shows up later as preoccupation with food, or a stronger pull towards eating more than the body needed in the first place.
Fat in context
Whilst there is no reason to fear fat, it can be helpful to remember that dietary fat is one food group and all food groups have their place.
If you've spent years avoiding fat, or feeling a flicker of guilt when you eat it, it might be worth noticing where that rule came from and whether it's actually serving you. Understanding what fat does for the body won't undo years of conditioning overnight, but it can be a steady, useful place to start.
