Does Eating Fat Make You Fat?
A popular message at this time of year tells us if we eat fat, we’ll gain weight. Although this statement makes logical sense, is it a nutritional myth?
In this article we’ll look at how we obtain energy from food and whether eating fat makes you fat.
Fat is Energy Dense
Food is comprised of carbohydrate, protein and fat all of which contain calories. A calorie is a unit of cellular energy.
If we consume more calories than we utilise, we’ll store the extra energy in fat cells for use at a later date. You may have heard the phrase ‘calories in minus calories out leads to fat’.
But are the calories in fat identical to the calories in carbohydrate or protein?
On the face of it, yes, and because fat is a concentrated source of calories, it makes that sense after eating fat we’d pile on the pounds. Fat contains nine calories in one gram compared to carbohydrates and protein which contain only four calories per gram.
The logical connection between eating fat and gaining fat has led to a plethora of low–fat diets and an ingrained tendency for people concerned about their weight to avoid high-fat foods.
However, the situation is not as simple as it seems, because fat is processed by our bodies using different metabolic pathways to those involved with carbohydrates and protein.
Fat and Weight Loss
If we believe a calorie is a calorie, diets containing identical amounts of calories but with different proportions of fat, carbohydrates and protein would lead to similar weight loss. This isn’t the case, with many studies finding low–fat diets don’t result in successful weight loss.
One problem with low–fat diets is people tend to continue eating refined carbohydrates – which have been stripped of their fibre – and these promote weight gain. Low carbohydrate diets seem to lead to more weight loss than do low–fat diets.
Fat and Energy Use
It appears eating fat means we burn slightly more calories, even without any increase in activity levels. Research has discovered this may add up to over three hundred calories per day. This is equivalent to the amount of energy expended in 90 minutes of lifting weights.
Fat and Blood Sugar
When we eat carbohydrate, enzymes in our saliva start to break it down into simple sugars. These travel quickly into the bloodstream, causing the release of the hormone insulin, which has the job of escorting sugar from the blood into the cells so it can be used for energy. So sugar in the blood will fall again and the body will tell us to eat.
On the other hand, fat digestion doesn’t start until food reaches the small intestine, so eating fat results in a far slower release of energy. Insulin doesn’t spike and the impact of fat on blood sugar is more subtle.
Fat and Appetite
The impact on fat upon the hormones which regulate our appetite also differs to that of carbohydrates and protein.
The hormone which makes us feel full is called leptin. Eating fat seems to activate this hormone as well as increase our sensitivity to its message. So fat appears to be more satiating than protein or carbohydrates, and this satiety effect lasts for several hours. Indeed, people following low–fat diets generally feel hungrier.
The net result is when we eat fat we stop eating sooner and feel full for longer. The type of fat found in butter or coconut oil appears to be particularly effective at increasing satiety.
So our body naturally regulates its calorie intake when energy dense foods containing fat are eaten, which makes perfect evolutionary sense to avoid obesity.
Fat vs Sugar
One problem with fat in the modern diet is it’s usually packaged with vast amounts of refined sugar, which stimulates our brain’s pleasure centres and make us want to eat more. Sugar also disrupts blood sugar levels, meaning we’ll end up feeling hungrier and with sugar cravings.
In contrast, fat seems to turn off the part of the brain related to cravings, so we usually don’t want to eat vast quantities of fatty foods.
All Fat is Not Alike
Habitually avoiding fat may lead to deficiencies in essential fats which, as their name implies, must be present in our diet as they are needed for essential body functions.
These include omega 3 fats, which are generally already scarce in the modern det because they’re easily damaged by food processing. Low levels of omega 3 can lead to, amongst other problems, a depressed metabolic rate which means we’ll burn off calories more slowly.
Fat and Our Personal Health
Of course we’re all different with unique genetics and health history. A consultation with a Functional Medicine practitioner can provide you with one to one support in implementing personalised dietary strategies and lifestyle modifications to achieve your health goals. Contact me to start your journey towards optimum health.