Fats and Your Genes: Facts versus Myths - Pathway Genomics
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Fats and Your Genes: Facts versus Myths

While “fat” is considered a dirty word in many people’s dictionaries, it is actually an essential macronutrient that plays a major role in your nutrition. However, genes impact how a body processes fat, which is why some people are more inclined to gain weight when consuming fats. Here, we’re looking at some of the relevant facts and biggest myths surrounding fat.

Myth: All Fats are Unhealthy

It’s true that some fats are best left uneaten, such as fried foods or greasy baked goods. But there are also beneficial fats. There are several types of fats found in foods, including:

  • Saturated fats
  • Unsaturated fats
  • Partially hydrogenated fats
  • Polyunsaturated fats
  • Monounsaturated fats
  • Essential and trans fatty acids
  • Omega-3 and omega-6 fatty acids

Trans fats and saturated fats are unhealthy fats, which can increase harmful LDL cholesterol and increase your chances of type 2 diabetes and heart disease. But polyunsaturated and monounsaturated fats and omega-3 and omega-6 fatty acids can do the opposite—decrease harmful cholesterol levels, build cell membranes and the covering of nerves and prevent heart disease.

Rather than eliminate fats entirely, you may instead focus on increasing your intake of healthy essential fats, such as eating more nuts, fish and avocados.

Myth: Eating Fat Makes You Fat

If you only look at fat in terms of calories, fat can cause weight gain (especially unhealthy fats), as fat contains nine calories per gram—five more calories per gram than carbohydrates or proteins contain. Eating too many fats would contribute to weight gain. However, unlike starchy carbs and sugar, fat doesn’t trigger the secretion of insulin, which is a fat storage hormone.

Just like carbs and protein, fats play an important role in your digestion but should be eaten in moderation. What’s more likely to contribute to weight gain is an unhealthy ratio of fats to carbs and proteins or the consumption of bad fats.

Myth: Fats Don’t Benefit the Body

Fat serves an essential purpose in your nutrition, and your body uses fat in several important ways. For one, fat is used in your body as a source of energy and fuel for activities. When your calorie intake is too low, your body can store fat for later use. This is what the ketosis diet is based on—reducing your carb intake to encourage your body to enter a state of ketosis and convert stored fat into ketones to fuel your cells. Fat also helps carry fat-soluble vitamins (like A, D and E), insulates your internal organs and maintaining your cell membranes.

However, a big caveat is that your body must process the fat into a usable form. This is why it matters what kinds of fats you eat, as it affects how your body processes and converts fats. When you first consume fats (which are typically triglycerides), a gland under your tongue secretes the enzyme called lingual lipase, and your stomach cells secrete gastric lipase. These two enzymes emulsify the fat and distribute the globules evenly. It takes more time for your stomach to digest fats than carbs or proteins, which is why higher fat meals can help you feel fuller for longer.

Your body digests most of the fat when it passes from the stomach into the small intestine. Here, the fat continues to emulsify and the pancreas secretes the enzyme called pancreatic lipase that breaks down the triglycerides into diglycerides, monoglycerides and free fatty acids. These fat components are smaller in size and absorbed by your intestinal wall’s cell layer.

The small fatty acids move to the portal vein, bind to the protein called albumin and go to the liver where they can be used for energy. The large fatty acids reform into triglycerides and release into the bloodstream as lipoproteins called chylomicrons. As they move through the bloodstream, they circulate triglycerides to your muscle tissue, fat tissue and liver where they can be used for energy or stored in fat tissue for later use.

Myth: Everyone Processes Fat the Same

Multiple studies have revealed that certain genetic variations can cause weight gain and a higher percentage of body fat when consuming fats compared to others without the genotype who eat the same amount of fat. Many doctors agree that genetics account for up to 70% of your weight variability.

For example, people with the genetic variation of ADRB2_2 are more prone to have a higher BMI and fat ratio, meaning they may struggle more with weight loss. On the other hand, those with the FTO gene causes fat cells to burn energy instead of storing it.

This means that if you’re genetically predisposed to gaining weight from fat consumption, it’s best to cut down on your fat intake and consider following a low-fat diet.

Myth: Everyone Will Benefit from a Low Fat Diet

Your genes play a role in how your body processes macronutrients, which is why you want to align your diet with your genetics. A low-fat diet is best for those whose genes struggle converting fat into energy. If your family has a history of heart disease or if you have high LPL cholesterol levels, a low-fat diet may be beneficial for you and help protect you from related diseases.

The best way to determine which diet is best for you is to take a genetic test, like Pathway Fit®, which provides you and your doctor with a genetically-matched diet designed to help you achieve or maintain a healthy weight. Understanding your specific genetic makeup can help you understand how your body reacts to and processes fats so you can find the ideal diet for you.