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Can low fat diet compromise my immune system?

Updated: Jan 31, 2023

Until fairly recently, low fat diets were hailed as the best option for weight loss. They were widely recommended to those looking to lose weight, and proved to be so popular that the food industry soon began mass-producing a whole range of low-fat foods. However, just like all of the other quick fixes out there, these low fat diets aren’t all that they are cracked up to be. Remember, if something sounds too good to be true, then it probably is. 

The low fat foods that proved to be so popular among dieters often contained the same, if not more calories than their full fat versions. These calories came from refined grains, sugar and even salt. In other words, low quality carbohydrates replaced fat. So, in an effort to dispel the myth that low-fat diets are great for weight loss, this article is going to look a little deeper at what is behind this intimidating word fat. It will look at the different types of dietary fat that we consume, which types of fat are to be avoided, and which will help to improve both your general health and weight loss efforts.

Fat is more important now than ever, simply because recently we all have become aware of Vitamin D needs. It is hard to believe, but even in the sun-shining states, we are still deficient. Vitamin D is fat soluble vitamin and this is something that we need to be cautious with. It needs to be taken with higher fat meals but how high? ConsumerLab advises to take it with the meals containing around 15 grams of fat. Higher fat meals must have less calories from carbohydrates. Even though, it is extremely rare but Vitamin D toxicity can occur. Simply because it is fat-soluble vitamin and our body doesn't have an easy way to get rid of it, unlike water-soluble vitamins. National Institute of Health advises around 15 mcg (600 IU) for an adult. The rate of supplement absorption is still unknown.


This is believed to be one of the worst kinds of dietary fat, though in actual fact studies show it is essential for a number of metabolic reactions, and is a key structural component of our cells. Our bodies use 100% of the cholesterol that it needs – it is only when we consume an excessive amount of it from animal products like meat, eggs and cheese that it begins to build up and clog our arteries. 

Trans Fat

Trans unsaturated fatty acids are bad fat and should largely be avoided. They are usually found in foods that have been through the process of hydrogenation – so things like commercially baked goods, frozen breaded foods and spreads like margarine. 

Saturated Fat

Studies show that saturated fatty acids should also be avoided. These are often found in various animal products like meat, poultry, and dairy, as well as in tropical plant oils like coconut oil, palm kernel oil, or palm oil.

Monounsaturated Fat

Monounsaturated fats, and more specifically Omega 9, are considered to be good fats. Add them in to your diet by eating foods like cashews, avocados, almonds, olives and peanuts.

Polyunsaturated Fat

Polyunsaturated fats are another source of good fats. These can be found in seeds, nuts, soy and corn. The polyunsaturated fats Omega 3 and Omega 6 are particularly important. Omega 3 is found in foods like walnuts, flax seeds and salmon; whilst Omega 6 is found in soybean, corn, and safflower oils. These fatty acids help to clean our arteries, and on top of that, Omega 3 fats have a positive impact on immune function.

Linoleic and Alpha-Linolenic Acids

These are what are known as essential fatty acids, meaning that they have to be obtained from food because our bodies cannot produce them. These fats are found in various cooking oils, flax-seeds, as well as in nuts, soybean, cottonseed and sunflower seeds.

Here we go, a brief rundown of the importance that fat plays in your diet. If however, after all of that you are still not convinced about the dangers of a low-fat diet, then consider the importance of the fat soluble vitamins A,D, K and E. The body cannot absorb these without fat, and they play a number of important functions within the body that help to support good health:

  • Vitamin A, which is found in any orange colored fruit or vegetable helps with vision. Deficiencies in this vitamin can cause night blindness.

  • Vitamin D is needed for calcium absorption, which is crucial for our bone health and immune system.

  • Even when the sun is shining, these days you still have to worry too much about vitamin D, but during the cold and dark winter months, don’t forget to fill your refrigerator with mushrooms. These are high in Vitamin D, which plays a number of important roles within the body.

  • Vitamin E is an important antioxidant that protects cells. It can be found in various cooking oils, and avocados.

  • Vitamin K is vital for blood coagulation, which prevents excessive bleeding. Green leafy vegetables like kale have been shown to be a great source of this vitamin. 

So unless you fancy being a weak boned, shortsighted individual who is prone to excessive bleeding, you should ensure that you are consuming enough of these vitamins in your diet. If that image alone wasn’t enough to convince you of the benefits of fat, then consider the role that it plays in digestion.

Although, fat is higher in calories than either carbohydrate or protein, it takes a lot longer to digest. This means that you will feel full for a long period of time and will be less likely to snack or overeat. Obviously you need to strike a balance, and fat should be included as part of a healthy, well-rounded diet. However, consuming about 20-30% of your daily calories from fat is a good idea, provided that they come from sources of good fat like Omega 3.


1.      CDC (2012) Nutrition for Everyone

2. Harvard School of Public Health. (2012) Fats and Cholesterol: Out with the Bad, In with the Good.

3. Cavallini, G. De Marinis, E. Donati, A. Marino, M. Martini, C. Pallottini, V. Strainier, S. Trentalance, A. (2008) Omega-3 as well as caloric restriction prevent the age-related modifications of cholesterol metabolism. Mechanisms of Ageing and Development. 129 (12). 722-727.

4. Millington, K. Reed, C. Simpson, S. The health benefits of omega-3 polyunsaturated fatty acids: a review of the evidence. (2004) Journal of Human Nutrition and Dietetics; 17, 449–459.

5. Mayo Clinic. (2013) Drugs and Supplements.

6.Chang, H. Cooper, J. Kozimor, A. Effects of dietary fatty acid composition from a high fat meal on satiety. (2013) Apetite. 69, 39-45.

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