Stating the Obvious: Fats Make You Fat…

You might have seen some of the headlines in the tabloid press recently

‘How eating a burger on Friday can make you feel hungry on Monday’ was one of the more memorable ones.

A recently published study from the UT Southwestern Medical Center confirms that fat from certain foods influences our brain chemistry.

Fatty acids integrate into the membranes of the nerves to alter brain-cell signaling that causes them to ignore the appetite-suppressing signals from leptin and insulin.

Leptin and Insulin are hormones known to be involved in weight regulation. One particular type of saturated fat (bad fat) – palmitic acid – is particularly effective at disrupting this mechanism.  Palmitic acid is found in high amounts in cheese, high fat dairy products, milk chocolate, non-organically reared pork.

Eating “bad fats” not only changes the composition of your cells for the worse, impacting on everything from concentration to the risk of cancer, but will actually make it more likely you’ll continue over-eating and continue with bad dietary practices.


Normally, our body communicates with our brain to indicate when we’ve had enough, but that doesn’t always happen when we’re eating something particularly tasty. In the rats studied, the effect lasts about three days.

This may go some way to explaining the phenomena of “falling off the wagon” in spectacular style: a binge on a Friday may keep you hungrier than normal until Monday morning.

The basic science behind “satiety-signals” or feeling full is fairly logical.

Certain hormones are produced when we eat, that not only influence our body chemistry, but also brain-chemistry, behaviour and eating patterns. The best known of these hormones is insulin, which is released in response to carbohydrate ingestion.

Insulin not only tells our body to store carbohydrate (with the surplus being stored as fat), and promotes muscle growth (a good thing), but also crosses the blood-brain-barrier (BBB) to influence our behaviour and stop us eating.

A similar hormone is cholycystokinin (CKK), it’s released from the gut around 30 minutes after eating.

This hormone stimulates nervous inputs to the brain in the gastrointestinal tract that make us feel full for a short time, although the effects are quick to wear off and this hormone is not thought to play a great role in appetite-regulation over the course of the whole day.

Leptin is produced from fatty tissue, not in response to feeding, but rather it’s influenced by body-fatness, weight-loss/gain and your body-clock.  So if you are already overweight then you will produce more Leptin that will continue to make you even fatter.  It’s the viscious circle again.

It is well established that eating a high-fat diet can cause insulin resistance, but less is known about the mechanisms that trigger this resistance or whether specific types of fat are more likely to cause it. As the brain is made of 60% fat (dry weight), its composition is determined by the fat we eat.  This may cause the incorporation of “good fats” or “bad fats” into the brains structure.

Do you want your brain to be made of ‘good fat’ or ‘bad fat’?

Researchers attempted to isolate the effects of fat on rats’ brains by exposing them to fat in different ways

Only the type of fat differed in the different groups, with each of 2 groups being administered either Palmitic acid (a “bad” saturated fat), or the monounsaturate oleic acid, found in olive oil.

Palmitic acid is a common saturated fatty acid occurring in foods such as butter, cheese, milk and beef, and is frequently added to convenience foods like ice-cream.

Palmitic acid specifically reduced the ability of leptin and insulin to activate intracellular signaling pathways in the brain, while the oleic acid did not do this.


eating the wrong type of fat actually causes you to eat more.

In addition, this mechanism is triggered in the brain long before the rats showed any other signs of obesity.   So you start getting fat even before you actually are fat.

Insulin resistance and its effect on obesity have frequently been compared to an explosion: it is self-perpetuating and up-regulates itself.

Once Insulin sensitivity decreases, the body increases the insulin released which reduces the effectiveness of insulin receptors, further impairing sensitivity.

In much the same way, eating bad fats not only puts these fats in your body, but seemingly encourages you to eat more of them. No wonder some people just seem to “blow-up” and get really big, weight gain can be like a snowball getting bigger as it rolls down the slope!

Ok so what can we do to prevent this from happening?

Action Steps

Insulin resistance in most cases can be reversed, you need to follow a diet like my Four Week Fat Loss program, you’ll need to restrict high glyceamic index foods like bread, pasta, and rice and eat more good fats.

Replace the bad fats with good fats. Not all saturates are bad, for example Virgin Coconut oil, made by Coconoil, can actually increase the rate at which you burn fat.

PUFAs (Polyunsaturated Fatty Acids), as can be found in the high-grade fish-oil supplements Aliment Nutrition  is the first I recommend  and can positively affect your brain chemistry and fat metabolism with a lot of research existing on Omega-3 and brain function.

A chromium supplement like Glucolean from Country life can help increase insulin sensitivity, meaning that your body and mind will combine to regulate your intake effectively.

About Matt Lovell

A sports nutritionist and brand ambassador for Kinetica Sports. Matt also runs his own elite performance based company called Perform and Function.

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