Been a while since I did a post on health so I’m here to drop knowledge bombs on the fat topic. My first post on health is too long and cluttered so I’m going to break things down to more bite-sized portions.
Let’s start with most important fact, something that a lot of people don’t know and have health issues because of: not all fat is bad. In fact, some fats are good for you. As in, actively help your health. Here’s something to think about. In the 1960s, fats and oils supplied Americans with 46% of their calories. At this time, about 13% of adults were obese and less than 1% had type 2 diabetes. Compare that with today where Americans only get about 33% of their calories from fats and oils, yet 34% of adults are obese and 11% have diabetes (stats sourced from Harvard).
So, what’s the deal here? Well, like I said, not all fat is bad. By reducing fat intake, people have also cut out good fats, and have replaced these with simple carbs (white bread, rice, etc.) which is a bad combination. Weight loss/gain is determined by the amount of calories. Other health issues depend on where these calories come from (fat, grains, etc.); for example, cholesterol levels can rise due to an increased intake of saturated fats, but you can still lose weight while eating saturated fats if you reduce your daily calorie intake. What’s that mean? Well, if you want to look good and be healthy, you need to watch what you eat and how much you eat. If you just want to look good for the short term (because if you’re unhealthy, you’re not going to look good for long), you can just eat less and not really watch what you’re eating (although some foods are far more calorie-dense than others).
How fat works:
So, let’s take a look at how fat works; fat is actually an important nutrient. Your body runs on three fuel sources, carbohydrates, protein and fat. I won’t go into detail here, that’s for another post, but basically fat provides 9 calories per gram whereas carbs and protein only provide 4. Fat is therefore a great source and store of energy. It also influences insulin sensitivity (will go into detail about this in another post) and can address inflammations. The body also uses cholesterol as the starting point to make estrogen, testosterone, vitamin D and other vital compounds.
However, fat and cholesterol don’t dissolve in water or blood, so the body packages fat and cholesterol into protein-covered particles called lipoproteins. These can dissolve into the blood stream. There are many types but the most important ones are low-density lipoproteins, high-density lipoproteins and triglycerides.
Low Density Lipoproteins (LDLs):
These carry cholesterol from the liver to the rest of the body. Cells latch on to the LDLs to extract fat and cholesterol from them. However, when there is too much LDL cholesterol in the blood, they begin to form deposits on the walls of arteries (called plaque), which narrows the arteries and limits blood flow. When plaque breaks apart, it can cause a heart attack or stroke. Because of this, LDL cholesterol is often referred to as bad cholesterol.
High Density Lipoproteins (HDLs):
These scavenge cholesterol from the bloodstream, from LDL, and from artery walls and ferry them back to the liver for disposal. Obviously, that’s good for you, which is why HDL cholesterol is often referred to as good cholesterol (as you can see, it actively improves your health).
These make up most of the fat that you eat and that travel through your bloodstream. They are the body’s main method for transporting fat to cells (good thing), but an excess can cause health issues.
Types of fat:
Ok, so now you know how fat works and that there are good and bad cholesterols (HDL and LDL respectively).
There’s two kinds of unsaturated fats: monounsaturated and polyunsaturated. These are called good fats because they can improve blood cholesterol, ease inflammation, stabilise heart rhythms and provide other health benefits. These kinds of fats are liquids at room temperature. Omega-3 is an important type of polyunsaturated fat because the body can’t make it. Most people don’t get enough of these healthy fats and the entire misled “low fat diet” only made things worse as people avoided bad and good fats, replacing them with simple carbs (which are bad). High fat diets with low carbs and healthy fats have been shown to result in weight loss and overall health improvements (such as reducing cardiovascular risks). The American Heart Foundation recommends 8-10% of your daily calories coming from polyunsaturated fats, though around 15% can do more to lower heart disease risks. The message here is to eat more healthy fats (and obviously less unhealthy ones).
Including trans fat (the worst), these are the bad fats you should avoid. They cause excesses of LDLs and triglycerides (their negative effects can be seen above), which lead to a wide range of health issues.
Some sources of good fats:
Oils: Olive, canola , flaxseed
Nuts: Almonds, hazelnuts, walnuts, pecans, peanuts
Seeds: Flax, sesame, pumpkin, chia
And fish, corn, and soybeans.
Although the Atkins diet and other studies have shown high fat diets do not necessarily lead to worse health conditions, that is a vast oversimplification of the issue. High fat diets are high in both saturated and unsaturated fats, the latter being good for you. When compared to a typical carb-rich American diet, it may be worth the increase in saturated fat to increase unsaturated fat intake. If you look at things more precisely though, it’s because high fat diets replace carbs as fuel, and because you’re getting more unsaturated fats (which you need). It’s not because the fat itself is good for you, it’s because people have really bad diets already, so the comparison is like picking the lesser evil.
As for why carbs are bad for you – well I’ll address that in another post but the crux of it is that carbs release glycogen into your system, and excess glycogen is stored as fat. High carb diets (especially simple carbs with a low glycemic index) tend to release too much glycogen at once, causing most of it to turn into fat. Carbs also digest the fastest out of the three fuel sources and cause blood sugar and insulin levels to spike, then crash very rapidly leading to feelings of weakness, tiredness, hunger and increasing risks of heart disease and diabetes.