How dietary fats affect health is one of the most commonly discussed topics in today’s world. Everyone, from amateurs to dietitians, nutritionists, and physicians, is talking about fats and cholesterol and the health issues related to them. But, would all our health problems be solved if we cut down fats from our daily diet completely? Unfortunately, the answer is no! We do need fats in our diet.
It’s the quality and type of fats, not their quantity, which really matters. For many years, low-fat diets or non-fat diets have been recommended for weight loss and prevention of various fatal diseases like a heart attack or coronary heart disease.
A lot of scientific data also supported the negative effects of fats on our health.
However, you will be surprised to know that, in recent years, research has proven that moderate-fat diet results in significantly more weight loss compared to total fat restricted diet 1)http://www.nature.com/ijo/journal/v25/n10/pdf/0801796a.pdf.
In the 1990s, low-fat diets were popular among the people despite the lack of any strong scientific evidence supporting such diets 2)http://authoritynutrition.com/7-ways-the-low-fat-diet-destroys-your-health/. Generally, fat-free or low-fat diet plans encourage us to switch to harmful food items which are made of ‘easy’ carbohydrates such as bread, rice, sugary juices or starchy foods. Such diets impose a great risk to our health by causing easily digestible carbohydrates to raise our blood glucose and triglyceride levels quickly.
This, in the long run, increases the risk of weight gain, diabetes and heart diseases instead of reducing the risk. Additionally, the low fat diets cause lower testosterone levels in the body, leading to increased body fat, osteoporosis, depression and decreased libido in both men and women 3)http://www.ncbi.nlm.nih.gov/pubmed/15741266 and http://www.ncbi.nlm.nih.gov/pubmed/6298507.
The American Heart Association’s (AHA) Nutrition Committee strongly advises having about 25 and 35 percent of your total daily calories as fats from foods like fish, nuts and vegetable oils 4)http://www.heart.org/HEARTORG/Conditions/Cholesterol/PreventionTreatmentofHighCholesterol/Know-Your-Fats_UCM_305628_Article.jsp#.
Now, a question comes in our mind that if it is officially recommended to consume 25 to 35 percent fats daily, can we live a healthy life without eating any type of fatty food? The answer is obviously no. The type of fat we eat is of utmost importance to maintain our health and wellbeing.
Some fats are potentially harmful while some are actually helpful to our health. Hence, what is required is not to cut all the fat from our diet but to be watchful about the type and quality of fat you are eating and ensure that it is as per standard guidelines 5)http://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/fat/art-20045550?pg=2.
Now that we have looked upon the misconceptions about the fat consumption, let us now have an overview of the metabolism and role of fat in our bodies.
Fat metabolism and function
Fat is a calorie-dense macronutrient, giving 9 kilocalories per gram consumed, which is more than double the amount of calories released from carbohydrates and proteins. Further, the fat is a huge reservoir and a great source of energy for later use when needed. Almost all food items on this planet contain at least some amount of fat; hence consuming some fats is inevitable no matter what diet plan we choose.
The dietary fats that we eat are in the form of triacylglycerols which get broken down to fatty acids before their absorption in the body by a process called hydrolysis of fats. These fatty acids then get absorbed into the intestine.
In general, the short-chain fatty acids directly enter the bloodstream and get transported to the liver where they are used for energy production 6)http://www.fao.org/docrep/v4700e/v4700e08.htm.
On the other hand, long-chain fatty acids first get absorbed into the intestinal cells, where they are attached to various lipoproteins, which are special packets that contain proteins and fats. This combination with lipoproteins allows long-chain fatty acids to move swiftly into the cells 7)http://www.news-medical.net/health/What-are-Lipoproteins.aspx.
The absorbed and synthesized fats then get stored throughout the body in the form of adipose tissue which is responsible for releasing energy as and when required by the body.
Now let us have a look at the various vital functions of fats. Fat is known as a standby source of energy when the carbohydrates are drained out. By doing this, fat safeguards the body’s proteins from being used up for energy.
This allows proteins to perform the more essential functions that is to build and repair body tissues 8)http://www.preservearticles.com/201012302088/functions-of-fats-in-the-body.html.
Another important function of fats is to help in the absorption and transportation of the fat-soluble vitamins- vitamins A, D, E and K all over the body 9)http://www.bci.org.au/about-breast-cancer/diet-and-lifestyle/diet-and-nutrition-about-bc-submenu-204/426-what-is-the-function-of-fat-in-our-body.html.
These vitamins are essential parts of your daily activities.
Other than these functions, fats, which are stored in the adipose tissue, provide insulation for our body. The adipose tissue forms a layer around vital organs of the body, such as liver, heart, kidneys and joints, keeping them guarded against sudden shocks or any outside shudders 10)http://healthyeating.sfgate.com/three-functions-fat-body-3402.html.
So, given all these important functions, fat should undoubtedly be an important part of your day to day diet.
Difference between fats and cholesterol
People often get muddled between the terminologies ‘fats’ and ‘cholesterol’. They assume that these two terms are interchangeable. But, fats and cholesterol are quite different from each other and are classified under the broader umbrella category known as ‘lipids’.
We do not use the word ‘lipid’ in our everyday conversation as it’s a more scientific term. However, let us see what lipids are. Lipids are organic compounds that are insoluble in water and blood. The various types of lipids include fats, oils, waxes, sterols (including cholesterol) and triglycerides 11)http://www.whfoods.com/genpage.php?tname=george&dbid=158.
The basic difference between dietary fats and cholesterols is that, fat provides energy in kilocalories, whereas cholesterol does not release the significant amount of energy. It is a complicated chemical compound 12)http://www.whfoods.com/genpage.php?tname=george&dbid=158 and http://www.livestrong.com/article/152434-difference-between-fats-cholesterol/.
Both fats and cholesterol are present in the food, are absorbed by the body and also synthesized by the body, mainly in the liver. However, an excessive intake of cholesterol can lead to increased health risks in terms of obesity and cardiovascular diseases as it contributes to plaque formation within our arteries.
Types of cholesterol
As mentioned above, cholesterol is a waxy, fat-like substance that does not dissolve in blood. Therefore, a transport medium is needed to carry cholesterol throughout our blood circulation. And those transport media are ‘lipoproteins’ which are made of lipids and proteins. There are three types of lipoproteins that transport cholesterol from cell to cell within our body. These are mentioned below:
- Low-density lipoprotein (LDL): It is called bad or harmful cholesterol. Excessive LDL cholesterol in the blood contributes to the deposition of fatty plaques on the inner walls of arteries throughout the body. These plaques narrow down the arteries by clogging them and making them less flexible. When such plaques become large enough to block the arterial blood flow, the condition is known as atherosclerosis. If not treated properly, sooner or later the plaques can break down and lead to heart attack and stroke. If plaque formation takes place in the arteries that supply blood to the legs, the person may develop a condition called peripheral arterial disease 13)http://www.heart.org/HEARTORG/Conditions/Cholesterol/AboutCholesterol/Good-vs-Bad-Cholesterol_UCM_305561_Article.jsp#. Various studies support the fact that elevated LDL cholesterol is a significant risk factor for developing fatal heart diseases. A research study was conducted in Japan to analyze the effects of LDL cholesterol levels and its relation to heart ailments. 2351 subjects more than 40 years of age were followed up for 19 years. The results showed a strong positive correlation between increasing LDL levels with rising incidences of coronary heart diseases and atherothrombotic infarctions (rupture of plaques surrounding the arteries) among the studied population 14)http://stroke.ahajournals.org/content/40/2/382.full.pdf+html. In contrast, reducing LDL cholesterol levels has proven to reduce the rate of major cardiovascular events 15)http://care.diabetesjournals.org/content/29/6/1220.full.pdf+html.
- Very low-density lipoprotein (VLDL): This type of cholesterol forms in the liver and then circulates into the bloodstream along with triglycerides. VLDL is also called as bad cholesterol. Similar to LDL, VLDL also contributes to arterial plaque formation and limits the blood flow through the arteries 16)http://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/expert-answers/vldl-cholesterol/faq-20058275.
- Triglycerides: After eating carbohydrates and fat some of them are used by our body for energy. But the excess energy of carbohydrates and fats which is not going to be used immediately get stored in the form of triglycerides in fat cells. On a regular basis, if your calorie intake is more than the calorie burnout, you tend to have a more triglyceride formation from the consumed carbohydrates and fats. Too much triglyceride in the blood is known as hypertriglyceridemia which has been identified as a risk factor for coronary artery diseases in numerous studies. Many prospective studies conducted in Western population consistently indicate a highly significant association between triglyceride levels and the risk of coronary heart disease, heat attack, ischemic heart disease and death 17)http://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/triglycerides/art-20048186, http://www.webmd.com/cholesterol-management/lowering-triglyceride-levels, http://jama.jamanetwork.com/article.aspx?articleid=208012&resultclick=1 and https://www.nlm.nih.gov/medlineplus/triglycerides.html. Additionally, an inverse relation has been identified between HDL cholesterol and triglyceride levels. A combination of low HDL and high triglycerides strongly leads to type 2 diabetes mellitus 18)http://circ.ahajournals.org/content/123/20/2292.full.pdf+html.
Further, if you lower the levels of triglycerides with diet and exercise, your VLDL levels will also automatically come down.
- High-density lipoprotein (HDL): HDL is the good cholesterol that benefits our heart in a number of ways. The main job of this protective HDL is to carry LDL and VLDL away from the tissues to the liver, where they are broken down and eliminated from the body in the form of bile and bile salts. HDL transports almost one-fourth to one-third of blood cholesterol to the liver 19)http://www.heart.org/HEARTORG/Conditions/Cholesterol/AboutCholesterol/Good-vs-Bad-Cholesterol_UCM_305561_Article.jsp# for elimination by a mechanism called as ‘reverse cholesterol transport’.
In addition, HDL helps to keep our blood vessels widened for easier blood flow. HDL cholesterol also reduces the inflammation of blood vessels by exerting its antioxidant and anti-inflammatory functions. Optimum levels of HDL cholesterol in the blood protect us against stroke and heart attack. Studies conducted on men and women worldwide have established that there is an inverse relationship between blood HDL levels and atherosclerotic disease.
It means, the higher your HDL, the lower you are at a risk of developing atherosclerosis. On the other hand, low HDL levels have been reported to increase the possibility of coronary artery disease and stroke 20)http://atvb.ahajournals.org/content/17/1/107.full and http://circ.ahajournals.org/content/111/5/e89.full.pdf+html. Regular exercise, maintaining healthy weight and choosing healthy fats in your diet will help in keeping the HDL cholesterol levels in the blood to optimum levels.
Hence, it is always important to focus on consuming “good” fats and avoid detrimental “bad” fats rather than going on a low-fat diet or non-fat diet 21)http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-and-cholesterol/. Now let us see how to consume good fats and circumvent bad fats in the diet.
Here is all about the fats that heal and the fats that kill!
Good fats are known as unsaturated fats. These are heart-friendly as they have beneficial effects on our heart such as stabilizing cholesterol levels and improving heart rate. Unsaturated fats are in a liquid state at room temperature unlike saturated fats 22)http://daa.asn.au/for-the-public/smart-eating-for-you/nutrition-a-z/unsaturated-fats/. Nutritionists and doctors always encourage the inclusion of unsaturated fats in our daily diet. Healthy unsaturated fats are found in two forms:
- Monounsaturated fats (MUFA): From a chemical perspective, MUFAs are fat molecules that have only one double bond that is made of carbon. They reduce bad cholesterol levels in the blood and eventually reduce the risk of heart diseases and stroke.
The foods high in MUFAs are vegetable oils such as olive, canola, sunflower, soy and corn, nuts, seeds like pumpkin and sesame seeds and avocados 23)http://www.heart.org/HEARTORG/GettingHealthy/NutritionCenter/HealthyEating/Monounsaturated-Fats_UCM_301460_Article.jsp#.VmIEofmrTIV and http://daa.asn.au/for-the-public/smart-eating-for-you/nutrition-a-z/unsaturated-fats/.
- Polyunsaturated fats (PUFA): PUFAs are fat molecules that have more than one unsaturated double carbon bond in the molecule. Like MUFAs, PUFAs are also healthy fats that prevent cardiovascular diseases. This type of unsaturated fat is again divided into two subtypes:
- Omega-3 fats: They have heart protective effects and help in reducing LDL levels (bad cholesterol), triglycerides and blood pressure levels. They also improve brain function, build up immunity and improve your mood. The food sources of omega-3 are fatty fish such as salmon, mackerel, herring and trout, eggs, deskinned chicken, flaxseeds, walnuts, soy and canola oil.
- Omega-6 fats: Research has proven that omega-6 fats reduce the risk of various heart diseases and make your skin healthy. They are found in sunflower, sesame, soy and corn oil, walnuts, pecans, Brazil nuts and sunflower seeds 24)http://daa.asn.au/for-the-public/smart-eating-for-you/nutrition-a-z/unsaturated-fats/.
AHA reports that MUFAs and PUFAs improve blood cholesterol levels and prevent us from heart diseases if they are used in place of saturated fats and trans fats 25)http://www.heart.org/HEARTORG/Conditions/Cholesterol/PreventionTreatmentofHighCholesterol/Know-Your-Fats_UCM_305628_Article.jsp#. This means swapping butter for margarine as a shortening and using unsaturated vegetable oils for cooking as a substitute to lard.
Such good fats when consumed with whole grains, fruits and vegetables can offer considerable protection against heart diseases.
Also, when this holistic diet is combined with regular exercise and physical activity, it may prevent us from metabolic disorders like diabetes and cardiovascular diseases 26)http://jama.jamanetwork.com/article.aspx?articleid=195543.
Going further, good fats can also become ineffective if high heat, light or oxygen damages them. Therefore, unsaturated fats should be stored in air-tight opaque container in a cool and dry place. Never reheat the cooking oil as the heat may bring about oxidation of oils that convert them to unhealthy fats. 27)http://www.helpguide.org/articles/healthy-eating/choosing-healthy-fats.htm.
Saturated fats are called bad fats. These fats do not have double bonds between their carbon atoms. They are called bad because they increase the blood cholesterol levels within our body and negatively impact our health.
For years, we have been known about the adverse effects of consuming saturated fats. The relationship between the saturated fats and heart diseases has been studied extensively for decades. The Nurses’ Health Study published in 1999 examined the association between the intake of individual saturated fatty acids and their food sources with the risk of developing coronary heart disease. In this prospective cohort study, 80082 women aged 34 59 years were followed up for 14 years.
The results indicated an inverse association between the consumption of PUFAs and coronary heart disease. On the contrary, high saturated fat consumption was linked with significantly greater risk of heart diseases 28)http://ajcn.nutrition.org/content/70/6/1001.full.
But recently, some studies have documented no relationship between the intake of saturated fats and the risk of cardiovascular diseases or coronary heart disease 29)http://ajcn.nutrition.org/content/early/2010/01/13/ajcn.2009.27725.full.pdf+html and http://link.springer.com/article/10.1007/s11745-010-3393-4.
However, the validity of such researches has been greatly questioned by the other investigators and hence their conclusions have not gained widespread acceptance 30)http://www.webmd.com/cholesterol-management/features/truth-about-saturated-fats.
A substantial amount of evidence indicates that replacing saturated fats with unsaturated fats (MUFAs and PUFAs) will lower the cholesterol levels in the blood and protect us from heart ailments.
Therefore, it is advised to cut back on foods rich in saturated fats such as fatty beef, lamb, pork, chicken with skin, lard, butter, cheese, whole milk, 2 percent milk, ice cream, coconut oil and palm oil 31)http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-and-cholesterol/ and http://www.heart.org/HEARTORG/GettingHealthy/NutritionCenter/HealthyEating/Saturated-Fats_UCM_301110_Article.jsp#.VmISo_mrTIU. It is best to consume them only in moderation.
When we say cut back on fatty beef, pork, lamb and butter, it means replace them with fish, deskinned chicken, nuts and healthy oils to have variety in your diet.
Very bad fats
Trans fats fall in the category of ‘very’ bad fats due to their definite health damaging effects. They are widely being accepted as unhealthy. Two types of trans fats are usually found in foods- natural trans fats and artificially made trans fats. Natural trans fats are present in the gut of some ruminant animals. So, the food items made from these animals, such as milk and meat products, may contain small amounts of trans fats. The second type of trans fat, artificial trans fats, are made in the industries from unsaturated fats.
Hydrogen is added to the unsaturated vegetable oils to make them more solid at room temperature and long lasting. This process is called hydrogenation and fats made by this procedure are labelled on the food packages as ‘partially hydrogenated oil’ 32)http://www.heart.org/HEARTORG/GettingHealthy/NutritionCenter/HealthyEating/Trans-Fats_UCM_301120_Article.jsp#.VmXwlfmDGko and http://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/trans-fat/art-20046114.
The process of making trans fats is inexpensive and these fats have a longer shelf life. That’s why they are produced by many food companies on a large scale. Additionally, trans fats make foods tasty.
Therefore, they are used by many restaurants and fast food outlets to prepare deep fried foods. Also, the oils containing trans fats can be used again and again due to their high smoking point. You will find trans fats in the food items such as cakes, biscuits, cookies, pizzas, donuts, crackers, chips, French fries, and margarine.
Such trans fats are considered harmful as they raise the total cholesterol levels by increasing LDL and VLDL and lowering good HDL. With this they truly promote the development of type 2 diabetes and cardiovascular diseases 33)http://www.heart.org/HEARTORG/GettingHealthy/NutritionCenter/HealthyEating/Trans-Fats_UCM_301120_Article.jsp#.VmXwlfmDGko. A 14 year follow-up study, conducted on 84204 women aged 34 59 years, suggested that trans fatty acid consumption increases the risk of type 2 diabetes mellitus, whereas PUFAs reduce the risk substantially 34)http://ajcn.nutrition.org/content/73/6/1019.full.
Few decades ago, margarine was considered as a healthy alternative to butter as it contains unsaturated vegetable fats. In contrast, butter was assumed to be health-damaging since it has high amounts of cholesterol and saturated fat percentage. Over the years, however, research has proved how margarine consumption is just as health-damaging as it increases the risk of coronary heart disease among consumers because of its high content of trans fats. 35)http://journals.lww.com/epidem/Abstract/1997/03000/Margarine_Intake_and_Subsequent_Coronary_Heart.8.aspx and http://www.drtimdelivers.com/EEasy122605/Harvardtransfats/transfats.html
Therefore, ideally, you should avoid eating trans fats completely. The AHA recommends cutting back on foods containing partially hydrogenated vegetable oils to protect yourself from heart diseases. The United States Food and Drug Administration (US FDA) permits food manufacturers to claim that a product contains “zero trans fats” if one serving of a particular food product has 0.5 grams of trans fats or less. The United States Department of Agriculture (USDA) recommends limiting the consumption of trans fats to a maximum of 2 grams per day. Many other authorities recommend removing trans fats altogether from your diet 36)http://www.drtimdelivers.com/EEasy122605/Harvardtransfats/transfats.html, http://www.helpguide.org/articles/healthy-eating/choosing-healthy-fats.htm and http://www.heart.org/HEARTORG/GettingHealthy/NutritionCenter/HealthyEating/Trans-Fats_UCM_301120_Article.jsp#.VmXwlfmDGko.
It is advised by experts to replace the trans fats in your diet with MUFAs and PUFAs. The AHA claims that adults who have reduced their trans fat intake and restricted the saturated fats consumption to 5 to 6% of total daily calories, have seen major benefits in the form of significant lowering of LDL cholesterol levels. 37)http://www.heart.org/HEARTORG/GettingHealthy/NutritionCenter/HealthyEating/Trans-Fats_UCM_301120_Article.jsp#.VmXwlfmDGko.
Dietary fats and metabolic syndrome
As we saw, the type of dietary fat we eat has a major effect on our health and wellbeing. For example, a high-fat diet can induce obesity, type 2 diabetes mellitus, and cardiovascular diseases. On the other hand, a restricted fat diet or inclusion of good quality fats in the diet can improve our health.
Let us see the correlation between dietary fats intervention and metabolic syndrome. The term ‘metabolic syndrome’ is a collection of diseases that are developed due to the alteration or failure in our body’s metabolism 38)http://www.mayoclinic.org/diseases-conditions/metabolic-syndrome/basics/definition/con-20027243. Nowadays, metabolic syndrome is becoming more common among people due to faulty eating habits and sedentary lifestyle. The cluster of metabolic syndrome includes following risk factors:
- Abdominal obesity or having an ‘apple shaped’ body, that is the deposition of excess fat in the stomach region
- A high triglyceride level
- A low HDL cholesterol level
- Increased blood pressure
- High fasting blood glucose or type 2 diabetes mellitus
These risk factors generally occur simultaneously. Having just one of these risk factors does not mean that you have encountered metabolic syndrome. You must have at least three metabolic risk factors to be diagnosed with metabolic syndrome 39)http://www.nhlbi.nih.gov/health/health-topics/topics/ms.
Now we will discuss some of the metabolic disorders and a significant contribution of dietary fats on their development as well as regression.
Dietary fats and cardiovascular diseases
For years, there has been a lot of talk about the relation between dietary intake of specific type of fats and the risk of cardiovascular diseases. This relationship has been studied extensively using many approaches. All lines of evidence come to the conclusion that specific dietary fatty acids play a crucial role in the development as well as in the prevention of cardiovascular diseases, while total fat percentage releasing energy is unimportant 40)http://www.ncbi.nlm.nih.gov/pubmed/22583051.
Therefore, diet is one of the key players which can change the game by impacting all cardiovascular risk factors.
A diet high in saturated fats and trans fats leads to increased levels of blood cholesterol. Whereas, the consumption of unsaturated fatty acids in the form of MUFA and PUFA has been reported to lower the risk of various heart disease. A 20 year Nurses’ Health Study, which included 78778 US women initially free of cardiovascular disease and diabetes, found the inverse association between PUFA intake and coronary heart disease, particularly among younger or overweight women.
Additionally, the results also demonstrated that there was an increased risk of coronary heart disease with trans fat intake 41)http://aje.oxfordjournals.org/content/161/7/672.full.
Earlier, a low-fat diet used to be the assured remedy for the prevention of heart diseases. Over the years, various reports have questioned the supposedly positive impact of low-fat diet on our heart health. This is because several clinical studies have indicated a similar risk of heart ailments in subjects who followed a low-fat diet and those who did not 42)http://jama.jamanetwork.com/article.aspx?articleid=202340.
A study published in the New England Journal of Medicine suggested replacing saturated fats and trans fats with non-hydrogenated MUFAs and PUFAs as an effective way of preventing coronary heart disease in women rather than reducing overall fat intake 43)http://www.nejm.org/doi/full/10.1056/NEJM199711203372102#t=article.
Therefore, the type of fat in the diet, not the amount of fat, is the most important factor affecting our heart health.
Dietary fats and type 2 diabetes mellitus
Just like cardiovascular diseases, there is a strong association between the kind of fat in your diet and the development of diabetes. Experimental data from numerous studies strongly supports the notion that diets high in ‘unhealthy’ fats such as trans fats and saturated fats lead to impaired insulin action as they increase blood cholesterol levels. Furthermore, people with diabetes are at a higher risk of heart diseases in the future 44)http://www.diabetes.org/food-and-fitness/food/what-can-i-eat/making-healthy-food-choices/fats-and-diabetes.html?referrer=https://www.google.com/.
On the other hand, replacing these bad fats with good and healthy fats such as MUFA and PUFA is likely to reduce the risk of type 2 diabetes. Among PUFA, omega-6 fatty acids are known to improve insulin sensitivity. Therefore, as a dietary practice, we must focus on including foods rich in unsaturated vegetable oils, nuts and seeds in our diet while avoiding high-fat meat, fat-rich dairy products, fried foods, lard, margarine and processed foods can help ward off type 2 diabetes 45)http://www.diabetes.org/food-and-fitness/food/what-can-i-eat/making-healthy-food-choices/fats-and-diabetes.html?referrer=https://www.google.com/, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2654180/ and http://www.sciencedirect.com/science/article/pii/S0163782708000593.
Dietary fats and obesity
It is a commonly held belief that the more dietary fat you eat, the more weight you gain. Fueling this belief are the numerous epidemiological studies that show a direct relationship between a high-fat diet and the chances of obesity. Dietary fat induces overconsumption of food and weight gain through its low satiety properties and high caloric density 46)http://europepmc.org/abstract/med/9225171.
Hence, weight watchers tend to focus on as low-fat diet to reduce weight. However, this is only a short-term weight loss. Various fad diets have been suggested by the health care providers for weight loss. But can you really lose weight by cutting back essential nutrients like proteins, carbohydrates, and fats through fad diets? The answer is no. These fad diets do more harm than good.
Again, it is the type of fat which is more important in weight loss regime. As evidence suggests, consuming good fats from whole grains, fruits, nuts and yogurt helps prevent obesity 47)http://www.nejm.org/doi/full/10.1056/Nejmoa1014296#t=articleTop.
Additionally, there should be an increase in energy expenditure with physical activities and a reduction in total energy intake to strike a proper balance of weight 48)http://ajcn.nutrition.org/content/68/6/1157.full.pdf+html.
Dietary fats and cancer
Many decades ago, there was a suggestion that high dietary fat intake could cause cancer. However, based on the current epidemiological studies, the recommendation to decrease the total fat intake for the prevention of cancer appears unjustified.
The Women’s Health Initiative Dietary Modification Trial which included 48835 postmenopausal women aged 50 79 years claimed that a low-fat dietary pattern intervention did not reduce the risk of colorectal cancer in the recruited subjects during 8.1 years of follow-up period 49)http://jama.jamanetwork.com/article.aspx?articleid=202340.
On the other hand, good fats have been shown to decrease the incidences of various cancers. Accordingly, supplementation with fats such as omega-3 fatty acid is considered to be chemo preventive as it modifies the risk factors for breast and colon cancer and as a result, reduces their incidence 50)http://www.sciencedirect.com/science/article/pii/S0163725899000261.
Also, the consumption of omega-3 fatty acids has a probable role in slowing down or stopping the growth of metastatic cancer cells 51)http://jn.nutrition.org/content/132/11/3508S.full. However, more vigilant research is warranted in this area to establish a validated link between dietary fats and cancer.
Few recommendations for dietary fat consumption
Above all the preaching by the nutritionists and doctors regarding fat consumption, we ourselves have to make diligent effort and choose our fats wisely. To lead a healthy life, we must stick to this message concerning dietary fats: Out with the bad, in with the good.
Before you grab a piece of pizza or a burger, take into account its nutrition value and its health effects. Keep your focus on the overall quality of the food. Here are some smart tips to help you choose your fat judiciously.
- Eliminate trans fat from the diet: The food products containing trans fats are made from partially hydrogenated oils. Therefore, look for the food items which say ‘zero trans fats’. Use nonhydrogenated vegetable oils such as canola oil, safflower oil, sunflower oil or olive oil for cooking. The commercially fried and processed foods like donuts, cookies, muffins, crackers and cakes usually contain trans fats, so limit the frequency of eating them.
- Read food labels: You will get an idea about the nutrient contents of a particular food by looking at the ‘Nutrition Facts’ panel. The US FDA allows 0.5 grams of trans fat per serving and such food can have a label of 0 grams trans fats. However, even this hidden small quantity of trans fats can add up quickly if you eat multiple serving of that particular food. In addition, you can also check the food product’s ingredient list for partially hydrogenated vegetable oil, which points out that the food contains some trans fat. Also, try to read the nutrition content table to see if the food contains high amounts of saturated fats and cholesterol.
- Cut back on saturated fats and consume more of fruits and vegetables: We need not have to eliminate the saturated fat from our diet completely. The USDA recommends limiting your saturated fat intake to 20 grams a day if your total calorie consumption is 2000 kilocalories per day. Try to avoid saturated fats that come from processed meats, red meat, packed foods and full-fat dairy products. Instead, replace processed and red meats with deskinned chicken, fish, and nuts.
Also, switch from whole milk and full-fat dairy products to low fat varieties. Do not go for high carbohydrate diets to avoid saturated fats. Even the refined carbohydrates such as white bread, refined flours, white rice or mashed potatoes can contribute to higher blood glucose and triglyceride levels. Focus on eating fresh fruits and vegetables, which will provide vitamins, minerals, fiber and good quality fats.
- Choose cooking oils carefully: Use unsaturated vegetable oils for cooking that remain liquid at room temperature instead of solid fats. For example, make use of olive oil for sautéing in place of butter. Among the various varieties of oils, choose a cooking oil that will keep you healthy and will itself stay healthy after heating.
This means pick cooking oils that have a high heating point and are resistant to early oxidation. Also, oils that hit the optimal MUFA: PUFA ratio are thought to be the best for cooking. The US FDA suggests 1: 1 to be the ideal ratio of MUFA: PUFA. Also, you can use cooking oils alternatively to get the maximum benefits out of each of them.
- Eat omega-3 fats daily: Consume omega-3 fatty acids on a day to day basis to keep your heart healthy. As your body cannot make omega-3 on its own, you must have them from external sources such as fish, vegetable oils, walnuts, flaxseeds, canola and soy oil.
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