This question has come up quite a lot at RWL, and as a researcher it’s one of those annoying questions that people just want a simple yes/no answer towards. However, that is almost impossible to give without more context and information.
Health itself is a complex issues to define. We have many superfit athetes with ripped bodies who may suffer from diabetes, digestive issues or even more prevalent mental disorders like depression. So, are they healthy? Also we may have someone who is very overweight, with certain biochemical markers that increases their risk of chronic disease but they exercise regularly, eat well and have a very positive outlook on life, with a great family network and social support. To be clear, health is very complex and to simply answer are low fat labelled foods actually healthier is really missing so much about health!
A slightly better question may be is low fat yoghurt, or low fat milk healthier than full fat yoghurt/milk. This is a direct food comparison where the same food has a lower fat content, and perhaps we can see if one food is “healthier” comparatively! However this is also impossible to truly answer, because a singular food item will probably have little effect on your health eaten on occasion compared to the overall aspects of other food, stress, exercise and sleep that is really affecting someone’s life!
“Just answer the question” I hear you cry! Ok.
“Low Fat” really became a fashionable based on some research by a famous nutritional researcher called Ancel Keys. To be very brief he showed what seemed like clear evidence that countries who ate the most fat had the highest rates of heart disease. It seemed like a clear correlation, the countries that ate the most fat had the most cardiovascular problems. He also seemed to suggest clear reasons for this, in that a specific type of fat, saturated fat increases “cholesterol”. Cholesterol leads to formation of plaques in small arteries near the heart and this is causative of much of the heart disease. Furthermore, Fat is much more calorie dense than other foods, so the more calories we eat, the more weight we put on. Being overweight or obese increases your risk of all chronic dieases and fat was seemingly a big contributor towards this.
Boom, problem solved…… Hence a big marketing campaign towards lower fat foods and the idea that eating fat simply made people fat. Surely this would solve our growing weight problem and reduce people dying from heart disease?
However, there was a problem. Despite an increase in Low Fat Products and lower fat consumption obesity rates continued to rise. In fact, they didn’t just continue to rise, they've skyrocketed quicker than ever, heart disease and diabetes also continued to increase.
Something didn’t quite make sense. A few problems with the original data came to attention. It seems Ancel Keys, the nutritional researcher we mentioned earlier, did something that in science is known as “cherry picking”. Where Ancel Keys only used about 6 or 7 countries in his original data, it seems when we looked at more countries and more data that a different story emerged.
As more countries were plotted into the data, the obvious association became less obvious. This led to a term called the “French Paradox” which showed that despite eating higher levels of fat than most countries, the French had lower rates of cardiovascular disease and longer lives.
Suddenly demonising fat was becoming more questionable. Even the Cholesterol argument was becoming murky also. There have been challenges to how much the food that we eat affects our cholesterol levels, and whether lower cholesterol, especially at certain ages really has much affect on cardiovascular health.
So what is a “low fat” product. To take the example of yoghurt again, which is generally a moderate fat food. For brevity sake, the fat is removed from the product. Often this effects the taste of the product and leaves the food tasting very bland, this is not good for food companies. What the companies realised is that to make the food taste half decent they needed to replace it with something that tasted good. Step in sugar!
As such low fat foods became high sugar foods. This may have been a problem because fat has a higher level on satiety than sugar. So it’s much easier to over eat and get those extra calories in with higher sugar foods. People thinking they may have been choosing a healthier food product, may actually have been doing no such thing. We also know that during the original demonising of fat, that many sugar companies threw their weight behind this push towards low fat, simply because it created a great business opportunity for them.
As time has shifted, it’s been very clear that blaming fat as the sole villain was perhaps a mistake. Too much fat, like too much anything can be a problem, but it’s also important to realise that fat is essential for our bodies, and that it’s very possible, as the growth in Ketogenic diets have shown, that fat loss is very possible even when eating a high fat diet, in fact for some it may be a lot easier, and there is interesting developments in research with Keto Diets and blood sugar regulation.
I fear however, we are swapping one villain for another. Whereas fat is being vindicated a bit, sugar has slowly become the new enemy. "Sugar makes you fat, sugar causes diabetes, sugar is as addictive as cocaine". My instagram feed basically tells me that sugar is pure evil. Sugar can be a problem, like fat if you consume too much of it, and perhaps high sugar foods are more likely to be junk foods, but sugar, in appropriate amounts don’t seem to be particularly evil. What the real problem has been this whole time is that we are all eating more of everything. In fact in the last 7 years sugar consumption is slowly dropping but obesity rates are still rising, of course calorie consumption per capital is also rising.
So although the low fat foods are now using sugar less, but using low or zero calorie sweeteners more, the problem is still apparent, but the real villain is that we are still eating too much of everything.
Sweeteners in low fat products have also come under scrutiny. Check out our sweeteners vs sugar article here for more information about this. But in a nutshell they don’t really seem to do anything particularly special and there may even be grounds for concern about how they affect your appetite and gut health.
So are low fat foods healthier? Probably not. However with a flexible diet that you are able to easily sustain, and a low fat yoghurt helps keep you consistently in your calorie deficit easily, whereas a high fat yoghurt would tip you over the edge, it may be a decent choice, but then again the higher fat yoghurt would leave you feeling more full, and perhaps you’d eat less throughout the rest of the day.
As I said in the beginning, it’s complicated. One thing we can be sure about is that low fat products have been “marketed” for years as being a healthier option, and this is certainly very debateable.