Dietary fats are just as important as any other macronutrient for there are many processes going on in your body that require fats. Fats don’t make you fat.
In fact this study conducted at Western Human Nutrition Research Center, California demonstrates that a low fat diet does not improve your cholesterol levels any better than a high fat diet.
Not only the quantity but also the quality of fats matter. That is why there are something called healthy fats which won’t make you gain weight.
Which fats are known as healthy fats?
Good fats are those that are naturally present in nuts, vegetables etc. They are known as unsaturated fats. Fats at a basic level are composed of carbon and hydrogen. Unsaturated fats are not saturated with hydrogen. There are two types:
Monounsaturated fats have a single carbon-to-carbon double bond. They are liquid at room temperature. Olive oil is rich in MUFA. And that is why people in Greece and other Mediterranean region enjoy low rate of heart disease despite of a low fat diet.
A polyunsaturated fat has two or more double bonds in its carbon chain. They are essential fats: that is your body can’t make them which is why you have to acquire them from food. The two types of PUFA are:
- Omega 3 fatty acids (n-3 fatty acids)
- Omega 6 fatty acids (n-6 fatty acids)
The numbers refer to the distance between the beginning of the carbon chain and the first double bond. Good sources of omega-3 fatty acids include fatty fish such as salmon, mackerel, and sardines, flaxseeds, walnuts, canola oil, and unhydrogenated soybean oil.
Foods rich in linoleic acid and other omega-6 fatty acids include vegetable oils such as safflower, soybean, sunflower, walnut, and corn oils.
Sunflower,sesame, pumpkin seeds
Why are these fats healthy?
The reason why unsaturated fats are considered healthy is that they have a positive influence on cholesterol and heart health. But there are a number of areas concerning the health that is affected by the quality of dietary fats.
We are now going to compare clinical evidence on saturated fats and unsaturated fats to determine why exactly are saturated fats preferred over the other fats when it comes to health.
1.Unsaturated fats improve overall heart health
The main health concern of dietary fats is their potential to clog blood vessels and cause heart diseases. The notion that has been spread since a long time is that saturated fats elevate levels of bad cholesterol and cause atherosclerosis.
However a meta-analysis (study of studies) revealed that there is no significant evidence that saturated fat is linked with increased risk of heart diseases. That being said you cannot skip the idea that unsaturated fats are better for heart health.
In a clinical trial, the effect of replacing saturated fats with unsaturated fats in diet was observed.
Marked reductions in total cholesterol, low density lipoprotein cholesterol and high density lipoprotein cholesterol were observed when saturated fats were replaced by polyunsaturated or monounsaturated fats keeping the calorie content same.
What does this mean?
Latest data reveals that saturated fat consumption is no longer a causative factor of heart diseases. But when you compare the two, unsaturated fats are more beneficial for cardioprotection.
2.They can reduce risk of diabetes
Type 2 diabetes is characterised by high blood sugar levels due to insulin resistance and lack of insulin. It is associated with obesity and can be managed with exercise and dietary change.
Salmeron et al have shown that total fat intake does not affect the incidence of type 2 diabetes but consumption of trans fat can increase and polyunsaturated fatty acids can reduce the risk.
A clinical trial by Summers et al. demonstrated that a diet rich in PUFA n-6 (e.g., linoleic acid) improved insulin sensitivity when compared with a SFA-rich diet after only 5 weeks. A Swedish study proved that a diet rich in MUFA improves insulin sensitivity compared to a diet rich in saturated fat.
What does this mean?
Although observational data reveals that recently diagnosed diabetic have high saturated fat intake there is not sufficient evidence to establish a cause and effect relation between the two. Nevertheless unsaturated fats reduce the risk of developing diabetes and improve insulin sensitivity.
3.Unsaturated fats are not likely to cause weight gain
Saturated fats have been associated with the risk of weight gain and obesity. A study focussed on reducing blood pressure revealed that high consumption of saturated fats was associated with greater weight and lower consumption was linked with lower body weight.
However polyunsaturated fats are generally an instant source of energy and not likely to be deposited as fat tissue. Mice fed corn oil (high in linoleic acid, the major dietary n-6 PUFA), only 31% of the intake was deposited, whereas 56% was deposited in mice fed a beef tallow diet (high palmitic acid, the major dietary Saturated fatty acid).
One study on obese men demonstrated that substitution of saturated fat with monounsaturated fat for 4 weeks was associated with significantly lower body weight and fat mass without a change in energy or fat intake. Studies also show that replacing saturated fats with polyunsaturated fats bring about reduction in abdominal fat.
A research study carried out for a period of 7 weeks compared the effects of overfeeding foods rich in saturated fats and unsaturated fats. Those who received saturated fats had markedly increased liver fat and a 2-fold larger increase in visceral fat compared with the PUFA group. On the other hand those receiving PUFA rich foods had 3 times more lean tissue.
What does this mean?
So when it comes to losing weight and especially the stubborn belly fat, unsaturated fats are your safest bet.
4.They reduce obesity induced inflammation
One of the most deleterious consequences of obesity is inflammation. Increased fat cells and increased deposition of fats leads to release of inflammatory chemicals. Inflammation is an appropriate immune response in presence of infection but otherwise it can damage tissue.
Saturated fatty acids stimulate inflammatory response and so is n-6 PUFA, also known as linoleic acid (LA) thought to be pro-inflammatory and it can be converted into arachidonic acid (AA) which serves as a precursor for inflammatory chemicals.
Kim-Tiu Teng et al have studied a great deal of clinical evidence as to how quality of fats can affect obesity induced inflammation. Their conclusion is high fat diet promotes inflammation irrespective of the type of dietary fat. However n-3 PUFA can aid in reducing inflammation.
What does this mean?
n-3 PUFA can moderately reduce the risk and also lower the intensity of obesity induced inflammation.
5.Omega 3 fatty acids are beneficial for Brain Health
The brain is rich in fats. Therefore it is reasonable to assume that composition of fatty acids has some relevance to brain function. Saturated fats play no role here. The fats that are said to affect the brain health are EPA and DHA.
n-3 fatty acids have been linked to possibly benefit in case of dementia, Alzheimer’s disease and age related cognitive decline. Evidence regarding this is rather confusing and those studies that oppose this idea do have certain limitations.
What does this mean?
n-3 fatty acids have an added advantage over saturated fats and that is that they are beneficial for brain health.
6.Unsaturated fats reduce onset of ageing related problems
High fat diet consumption is associated with increased mortality and incidence of metabolic diseases. But many studies show that diets rich in unsaturated fats lower cholesterol, blood pressure and risk of cardiovascular disease and all of these factors affect longevity.
Certain polyunsaturated fatty acids prevent aging associated diseases. Arachidonic acids, which are n-6 fatty acids cause death of cancer cells. n-3 fatty acids prevent age related damage in the brain. Cell culture studies show that n-6 fatty acids increase lifespan.
What does this mean?
Unsaturated fatty acids protect the heart and prevent onset of metabolic diseases and thereby promote longevity.
Saturated fats: Good or Bad?
We have been told that saturated fats are the ones that cause heart disease. Back in 20th century scientists on the grounds of animal studies felt that it increases the cholesterol levels which lead to heart disease.
However lately it is felt that there is not enough data to suggest cause and effect relation between the two. Additionally an important point put forward by Glen D. Lawrence in his paper Dietary Fats and Health: Dietary Recommendations in the Context of Scientific Evidence is that perhaps the food that is rich in saturated fats and is blamed to cause heart disease has other components which cause metabolic diseases.
For example the minor content of PUFAs in meat is oxidised on cooking and also the high temperatures may oxidize carbohydrates. These oxidation products can promote oxidation stress that lead to diabetes and cardiovascular risk. So cooking style could be one causative factor and also replacing saturated fats with refined carbohydrates can lead to heart diseases.
One natural source of saturated fats that is really healthy is coconut oil and palm oil. This is because the chain length of saturated fatty acids also affects the cholesterol levels. Coconut oil contains medium chain fatty acids which are healthy. Read more: Coconut for weight loss
How to include healthy fats in your diet?
It is not that easy to replace saturated fats with unsaturated fats. This is because unsaturated fats are subject to oxidative rancidity. But here are a few things you can do to include healthy fats in your diet:
- Cook with olive oil or coconut oil.
- Snack on healthy fats sources like nuts and avocados.
- To pamper your sweet tooth eat dark chocolate.
- Use nut butter.
- Full fat Greek yogurt is safe.
- Take fish oil supplements or consider eating fish 2-3 times a week.
- When cooking at high temperatures use an oil that has high smoke point.
- Go for lean cuts of meat and go for ‘organic’ or ‘grass fed’ red meat.
- Avoid deep frying.
Apart from trans fat, all other fats are good if you exercise moderation. But the true winners are unsaturated fats.
Its not easy to shift from saturated to unsaturated fats but its not impossible either and nowadays people have learnt how to make healthy food tasty. Start making healthier choices.