As fad diets have come and gone, their myths have stuck around. In particular, the nutritional belief that fat in food can equivalate to fat on your body. Yes, it is true that the overconsumption of anything can lead to weight gain [usually resulting in excess body fat], and yes it is true that fat is calorically twice as dense as carbohydrates and proteins, but this does not mean that eating dietary fat as a part of a balanced diet will automatically lead to fat gain.
As we have begun to explore the different types of macronutrients, hopefully you’ve started to recognize a common theme...not all foods are created equally. In the realm of dietary fat, there are three major types: unsaturated, saturated, and trans fats.
These are the healthiest types of fat - also known as ‘heart-healthy fat’ - because they remain a liquid at room temperature and are found in the least processed form of plants and animals, and contribute to healthy levels of both HDL & LDL cholesterol.
There are two types of fats that fall under this category, monounsaturated fat and polyunsaturated fat. Below are examples of food items within each category.
Monounsaturated fat: avocado, , peanut butter, nuts [almonds, cashews, peanuts, pecans], vegetable oils [canola, olive, peanut, safflower, sesame]
Omega-3: eggs (including omega-3 enriched), flaxseeds and flaxseed oil, walnuts, soybeans, tofu, canola oil, fortified foods like some margarines, juices and yogurts
Omega-6: soybeans, corn, safflower and sunflower oils, nuts and seeds, meat, poultry, fish and eggs
Saturated Fats
Saturated = solid. Saturated fats are solid at room temperature, and mostly found in animal products, specifically dairy products, red meats [lower levels found in poultry and fish] and tropical oils. This of course means that foods made with any of these products are also contain saturated fats aka processed foods such as baked goods, desserts and fried foods. This type of fat is less than ideal because of its negative effect on LDL levels. Here are some examples:
Dairy products: milk, cheese, butter, margarine, shortening, lard, cream, ice-cream, sour cream
Meats: fatty beef, lamb, pork, poultry with skin & dark meat, beef fat
Tropical oils: coconut oil, palm oil, cocoa butter
Trans Fats
Trans fats is short for “trans fatty acids” and appears in the foods that contain partially hydrogenated vegetable oils. Many people dub trans fats the worst type of fats because of the process the fat has undergone, called hydrogenation, which increases the shelf life of that fat by making it hard at room temperature. This processing contributes to the lowering of your good cholesterol [HDL] and the raising of your bad cholesterol [LDL]. The types of foods industrial trans fats can be found in are:
Fried foods: French fries, doughnuts, deep-fried fast foods
Stick margarine, salad dressings, vegetable shortening, non-dairy coffee creamer
Baked goods: cookies, cakes, pastries, ready-made frosting, canned biscuits, frozen pizza crust, cinnamon rolls
Processed snack foods: crackers, potato/corn/tortilla chips, microwave popcorn
So why are some fats better for you than others? It has to do with their effect on our health, particularly, our heart health. You know what this means, cholesterol levels! The main reason fats are considered ‘good’ and ‘bad’ is because of their affect on our cholesterol levels. Now, for those of you who didn’t know, cholesterol is actually a type of fat that our body needs in order to help make Vitamin D and hormones such as estrogen and testosterone.
HDL or high-density lipoproteins aka “good cholesterol” transports excess cholesterol to our liver to be expelled from our body - we want this number to be high
LDL or low-density lipoproteins aka ‘bad cholesterol” is though to transports cholesterol to our arteries [where if it builds up - becomes plaque - we are at risk for blood clots, reduced blood flow, strokes, heart attacks] - and we want this number to be lower
There are other lifestyle factors that contribute to your cholesterol numbers that are not just related to one’s diet, such as obesity, waist circumference and lack of regular exercise.
In continuation of last week’s article on the importance of dietary fat, here are some physiological symptoms that people may experience when they are not eating enough fat [i.e. have a fat deficiency].
Skin Trouble: dry/flaky/itchy skin, scaly rashes, wounds that won’t seem to heal
Cognitive Problems: learning deficits, increased risk for certain types of dementia
Vision Issues: dry eyes, retinal problems and macular degeneration
Hunger: fat provides satiety, therefore curbing overeating
Body Temperature Regulation: too low body fat = complaints of being cold
Neurological Abnormalities: extreme mental fatigue, lack of concentration, trouble remembering, lack of mental energy
Amenorrhea: lack of menstrual cycle [caused by over-exercising, low body-fat, other hormonal imbalances] - essentially your body’s way of telling you it’s not well-nourished enough to support pregnancy
Eating low-fat will not necessarily lead to weight loss. As we know, to sustain life, one must continue to eat foods...and if you have eliminated or significantly reduced a type of food that helps keep you fuller longer, chances are you are supplementing with other types of foods - not necessarily the highest quality foods either. If you’ve supplemented your calories with simple carbs can lead to spikes in insulin [stimulates hunger & fat storage], drops in blood sugar which lead to cravings. And, most importantly, if you are stressed [perhaps in a continuous chronic low level stress response due to dieting, or a higher stress response due to external factors] you will certainly have higher levels of the stress hormone cortisol [which muffles satiety, causes cravings] which will make it extremely difficult to lose weight.
The moral of the story here is to continue learning what a balanced diet looks like for you. Unless suggested otherwise by medical professionals, you need to eat ‘smart’ foods from all of the macronutrient categories. If you're unsure if your current diet is in your best interest and you are managing health conditions please reach out to any medical professional that you may be under the care of for a referral to a Registered Dietician or Nutritionist.
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