Sugar Versus Fat – What We Learnt

On Wednesday 29/1/14 the BBC screened a Horizon program entitled “Sugar Versus Fat – Which Is Worse?”

The program asked two identical twin brothers – both of whom are medical practitioners – to follow either a high fat or high sugar diet for a month to see what effect such a diet had on their health.

They particularly looked at how body fat levels, body muscle levels and insulin levels were influenced by either diet, and drew some critically important conclusions that are relevant to us all, despite the fact that this was a short experiment involving only two people. Here are the key points the program made:

Is sugar worse than fat, or vice versa?

The question is too simplistic to have any real meaning. Both sugar (as a form of carbohydrate) and fat play vital roles in allowing our cells to function properly to keep us healthy, but excessive quantities of either one of these macronutrients is bad for us.

However, nutritionists believe that neither of these two individual factors by themselves is responsible for the burgeoning epidemics of obesity, diabetes and other lifestyle diseases that plague modern societies.

Fat And Sugar – A Deadly Combination

The issue is not fat or sugar; it’s fat and sugar!Icecream iStock_000080833957_Medium

Our brains “hedonic pleasure centres” find it particularly difficult to resist the seductive pleasure of the combination of sugar and fat. This deadly combination of fat and sugar is a manufactured phenomenon – you can’t find it anywhere else in nature, and in the face of such an abundance of energy dense, calorie packed processed “foods” it’s almost astonishing that any of us manage to stay slim!

This combination of fat and sugar engages the brains hedonic pleasure centres much more powerfully than either sugar or fat alone, and overpowers our brains ability to tell us to stop eating, leading many of us down a path that results in ill health, weight gain and a “big belly blow out”.

So do yourself a favour and cut out (or at least cut back on) the discretionary “treats” such as ice cream, chocolate, donuts and many other processed foods, and develop a holistic attitude to food, based on the importance of a balanced diet that avoids processed “foods”.

All Faddish Diets Are Wrong Or Incomplete

Say no more.

The Pros & Cons Of The High Sugar Diet

There are no long term health benefits associated with a high sugar diet, but there are plenty of disadvantages associated with such a regime.

Once again, sensible nutrition is all about balance. The Horizon program demonstrated how we need glucose as a vital energy source for powering our body, whether that be to sustain concentration and mental alertness as per the programs stock broking experiment, or whether it be to power our muscles to get us up a hill in a cycling duel.

However, excessive energy  intake – particularly in the form of fructose – over a sustained period of time causes us to develop a fatty liver, and is a key driver in developing many of the lifestyle diseases that plague modern societies, including insulin resistance, diabetes, heart and blood vessel disease, high blood pressure, strokes, liver disease,  many forms of cancer, and others.

The Pros & Cons Of The High Fat Diet

Again, there are no long term health benefits associated with a high fat diet, but there are plenty of negatives associated with such an approach.

Fat (especially good fats such as omega 3 and monounsaturated fats) is a vital source of energy and plays a key role in maintaining the physical wellbeing of our body, but a high fat diet also has its problems, as this program demonstrated.

Conventional thinking still links the consumption of too much fat (especially saturated fat) with elevated blood cholesterol (especially the “bad” LDL cholesterol), although this theory is being questioned. However, there is no doubt that man made trans fats are really bad for you, depleting your body’s levels of the protective “good HDL cholesterol” and leaving you prone to strokes, heart attacks, and many other serious health problems.

But the program also highlighted a couple of other key (but lesser well known) points about a high fat diet, namely:

  • High fat diets cause the body to start to burn muscle tissue as fuel.Butter curls

With very little dietary blood glucose, the body of the brother on the high fat diet started to break down its own muscle tissue in order to convert the amino acids that were liberated into glucose. In other words, even though he did lose some body fat, he lost an equal amount of muscle tissue as the body burnt its own muscle tissue in order to supply its need for glucose.

You can power your body without sugar like this for a while, but the price you pay is muscle loss as your body burns muscle to make sugar. Exercise like that all day and you’ll lose muscle tissue, but keep most of your body fat.

All in all, this is not a very clever long term strategy for health, as it’s really important to preserve your body’s muscle mass, and muscle loss is closely associated with increased risks of hospitalisation and poorer life expectancy.

Remember, it’s not just about losing weight, it’s about where that weight loss comes from, and a dietary regime that causes you to burn muscle tissue to supply your body with energy is not a good idea.

  • High fat diets lead to increased insulin resistance

After just one month the brother on the high fat diet came very close to being classified as diabetic.

As his body was being starved of glucose not only was it breaking down muscle tissue to convert amino acids into glucose, but his pancreas was also pumping out much higher quantities of insulin to ensure that that glucose produced in this way found its way into his cells to fuel their need for cellular energy.

However, at the same time, insulin stimulates fat synthesis within the body, and causes the body to hold onto fat more stubbornly, thus increasing overall body fat levels. The net effect is that he gets fatter over time, his body fat levels increase, his cells become increasingly resistant to the effects of insulin, and in an attempt to pump out even greater quantities of insulin his risk of pancreatic burnout (i.e. diabetes) increases.

Remember, this process was starting to become apparent in this particular brother after just one month on his high fat diet, but the reality is that this pre diabetic state (and the Type 2 Diabetes that follows on from it) is one of the most common and rapidly growing health issues facing the modern world.

High Fat Meals Can Have Less calories Than High Carbohydrate Meals

At first glance this seems strange as a gram of fat has roughly double the calories of a gram of carbohydrate, but meals with a significant amount of fat in them also usually have a significant amount of protein. Protein suppresses the hunger hormone “ghrelin”, so we tend to feel “fuller” more quickly when consuming protein.

As a result, even though the calorie density of a fat based meal is greater, the protein within it usually causes us to eat a smaller meal than if the meal was largely carbohydrate based, meaning that we consume less calories overall.

Carbohydrates Are Critical In Fuelling Sports Performance And Muscle Recovery After Exercise

iStock_000048338466_Medium cyclists

He got both brothers to cycle for an hour to exhaust their muscle carbohydrate stores, then gave each brother an equal amount of calories, one in the form of fat (a knob of butter) and the other in the form of carbohydrate (an energy bar). He then asked them to race up a hill on their bikes.

The brother who had consumed the carbohydrates won fairly easily, whilst the brother who had consumed the fat bonked out and had nothing left to give, demonstrating that carbohydrates are a superior form of energy in maintaining muscle function in exercise, and in recovery after exercise.

However – as expected – the brother who had consumed the carbohydrate gel had higher blood sugar levels after doing so, but so too did the brother who had consumed the knob of butter.

The difference was that the first brother’s elevated blood glucose came from his energy bar, whereas the second brothers elevated blood glucose came as a result of his body breaking down muscle to convert the liberated amino acids to glucose to sustain his energy levels.  This latter situation is obviously self defeating, and in Mitchells own words would get him the sack if it was pursued in a professional sports environment.

You Need To Keep Exercising To Retain Muscle Mass But You Must Feed Your Muscles Properly

Muscle tissue is effectively a type of organ that helps you regulate blood sugar levels, insulin levels, and your metabolism right throughout your life.

You need to keep exercising to retain muscle mass throughout your life, but you must also feed your muscles properly, and carbohydrates (as part of a balanced diet that also includes fat, protein and various other vitamins and minerals) play an important role in this.

Changing Fat Or Sugar On Their Own Has Very Little Effect On Obesity

Overall, in terms of population rates of obesity, changing fat or sugar consumption on their own has a very small effect, especially for the goal of losing or gaining weight. Of far more importance is the combination of fat and sugar, and their contribution to total calorie intake.

You Can’t Get Porridge Oats On The Continent Of Europe

MarkCavendish-NigelMitchell-620x349Wow, we didn’t know that! Porridge is a fantastic source of healthy sustained energy, but evidently Team Sky’s nutritionist Nigel Mitchell is unable to get it for his team when they are cycling on the European continent.

As a result, he can often be seen clearing out his local supermarkets of up to 80kgs of porridge oats at a time just before they travel to Europe to train or compete, and that is something we definitely didn’t know before!


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