Sugar, oxygen and athletic performance

Athletes that push their bodies to the limit need to fuel up with the right energy. That means choosing the right type of carbohydrate. Dr Coy’s research looks at how different sugars affect oxygen transport, the way muscles release energy, and the flexibility of the proteins in ligaments and muscle.

Most athletes are encouraged to follow a high carbohydrate diet for top performance, and to eat plenty of protein to help their bodies repair and rebuild after exercise. But many athletes don’t realize that the wrong sugars and too much protein can have some harmful effects. The consumption of sugars and carbohydrates which lead to high blood glucose levels increase the chemical modification of proteins by sugars – the so-called advanced glycation end products (AGE’s). Flexible proteins like elastin are no longer elastic if glucose is attached to it. Stiffness of proteins (like ligaments and muscles) increase the risk of ruptures – ligament ruptures as well as torn muscle fibre. Injuries caused by sugar related protein modifications are not only painful but can be difficult to recover from.

The problem with too much protein and too many carbohydrates

A low carbohydrate diet is one way to keep blood glucose levels stable and maintain the optimal amount of body fat. However, when the body burns protein for energy instead of carbohydrates, this creates amino acids which produce ammonia when metabolised. Ammonia is toxic, which means diets that are too high in protein bring their own problems.

This leaves the athlete with a problem. Eating a lot of classic sugar and starch raises blood glucose, and that sugar attaches itself to proteins and makes ligaments and muscle stiffer, which is how the injuries described above happen. Cutting the carbohydrates right back avoids that, but then the body has to burn protein for energy instead, and burning protein produces ammonia. Either way there is a cost.

Any sugar solves the ammonia half of the problem, including ordinary sugar, because once there is sugar available for energy the body stops breaking down protein and no ammonia is made. The trouble is that ordinary sugar then causes the first problem instead. Dr Coy’s research points to a way round this: keep sugar in the diet so the body is not forced to burn protein, but use sugars that do not send blood glucose high in the first place… continue reading

The problem is that classic sugars cause blood glucose levels to rise, which can create a sugar coating on proteins in the blood and hinder oxygen transportation around the body. In muscles, glucose attached to proteins makes connective tissues less flexible, which can cause muscle and ligament injuries.

Boosting energy using classic sugar products raises blood sugar levels and reduces flexibility in muscles, tendons and other connective tissues, putting them at risk of injury. Eating simple carbohydrates found in sugary drinks and snacks can also cause dental issues among athletes.

Galactose goes a step further on the ammonia question. Dr Coy’s research describes how, when galactose is available, the body builds it into the glycogen stores alongside glucose. Two things follow. Glycogen that contains galactose is broken down more slowly, so the stores last further into a competition. And as that glycogen is used, the galactose it contains is released at exactly the moment the body may start burning amino acids for energy. The amino group left over from that process is transferred onto the galactose, forming an amino acid, which is how the ammonia is dealt with before it can accumulate.

Dr Coy’s sugars as an alternative energy source for athletes

Switching from classic carbohydrates to one of Dr Coy’s sugars such as galactose or trehalose supplies energy without the body having to break down protein for it, so the excess ammonia does not arise.

Athletes need plenty of oxygen to reach their muscles, and the glucose found in classic sugars interferes with that. One of Dr Coy’s sugars, trehalose, is composed entirely of glucose, yet it has a low glycaemic index, so it releases that glucose gradually rather than all at once. Dr Coy’s research shows this is a way of taking in glucose without the sharp rise in blood glucose and insulin that normally comes with it.

Because trehalose is made of glucose and nothing else, it releases no fructose at all. The glucose is immediately usable by the body, and the effects that high concentrations of fructose have on liver metabolism do not arise. Isomaltulose, which releases glucose and fructose together, breaks down even more slowly, and Dr Coy’s research shows it increases muscular performance in endurance and speed compared with maltodextrin, the hydrolysed starch used in most sports drinks.

Sports drinks and energy bars that contain classic sugars may provide a quick energy boost, but over the long term they bring the glucose spikes that cause the protein damage described above… continue reading

Consumption of sugars leading to high blood glucose levels cause chemical modifications in haemoglobin by sugars. Glucose attached to haemoglobin is being routinely measured in diabetes patients (HbA1c), but can also be used for monitoring the nutrition related performance of athletes. Haemoglobin is the protein transporting the oxygen in the blood vessels. The more glucose is attached to haemoglobin, the less efficient the uptake of oxygen is in the lungs and the delivery of oxygen to muscles and other organs. The glucose coating the haemoglobin therefore leads to less efficient oxygen transport.

This is why Dr Coy regards HbA1c as a measurement worth watching in athletes, and not only in people with diabetes. His research concludes that an athlete’s oxygen transport is partly a function of what they have been eating over the preceding three months.

Galactose and the mitochondria

Many sports are dependent on an oxidative energy release using mitochondria. The higher the oxidative energy release, the better the performance. The switch from this aerobic energy release towards an oxygen independent energy release is characterized by the VO2max, the maximal performance in this aerobic condition. As soon as not enough oxygen is available to release sufficient energy, an oxygen independent metabolism for energy release is being started, the fermentation of glucose to lactic acid. Muscles start to produce lactic acid, and this can be measured by a blood test. The slower the muscle starts the fermentation and lactic acid production, the longer a muscle can perform on the long term. In the short term, muscles are able to release energy by fermentation of glucose to lactic acid, a kind of turbo boost, which helped our ancestors survive critical fight and flight situations. Except for a few sports like 100m sprints, most sports depend on performance in aerobic conditions, or a combination of performance in aerobic conditions and short-term fermentation e.g., sports like football, tennis etc.

The different effects of galactose and glucose

Each sugar has a very different effect on the metabolism. Glucose can easily be used for fermentation metabolism. Galactose, on the other hand, must first be converted into glucose to be used for fermentation metabolism. To do this, the cell must invest as much energy as is subsequently released. The bottom line is that galactose provides no energy when it is used for fermentation. Therefore, the cell has no choice but to reactivate the mitochondria (combustion engines) to obtain energy from galactose. As a result of the activation of the combustion engines, the mobilisation and burning of fat is also increased.
Study results show that the consumption of galactose while still eating increases fat mobilisation and fat burning in overweight people. For biochemical reasons, galactose forces the use of mitochondria which increases the use and burning of fats in the body. This is the basis of Dr Coy’s interest in galactose as a way of training the mitochondria and the body’s capacity for oxidative metabolism (oxidative phosphorylation)… continue reading

This has been measured directly in human muscle. In a 2013 study published in PLoS One, researchers took muscle cells from healthy adults and grew one set on glucose and another on galactose. The galactose-grown cells showed higher oxidation and a higher mitochondrial content. Mitochondria are the parts of the cell that burn fuel using oxygen, so more of them means more capacity to produce energy aerobically. The comparison Dr Coy draws is with cardiovascular training: just as endurance work over time improves the way the body uses oxygen, galactose appears to train the muscle’s own use of oxygen.

Dr Coy’s research follows from this. Both ketogenic diet and fasting exhaust the glucose deposits (glycogen) in the body and cause an oxidative metabolism with the mitochondria. Galactose does the same thing without removing carbohydrate altogether, which is why he combines them. In his model, training an oxidative metabolism in this way is what underpins performance in aerobic conditions (VO2max), and a later switch to oxygen independent fermentation.
Dr Coy’s sugar mixtures can be used to improve training. Tagatose should be integrated in the training phase because tagatose stabilizes blood glucose levels even when other sugars that raise blood sugar levels are consumed, because tagatose slows down the uptake of other sugars. Tagatose is also fermented by bacteria in the large intestine, which produce the short-chain fatty acid butyrate.
In Dr Coy’s sugar mixes for sports competitions, tagatose should be replaced because the energy content is low, and because the fermentation that follows it is not wanted during an event. Ribose, a sugar which is a direct precursor for ATP should be integrated instead. In addition, trehalose as a glucose source and isomaltulose as a source for glucose and fructose delivers sugars for energy release.

Using Dr Coy’s sugars in training and competition

Create your own sports drinks using water and Dr Coy’s sugars for training and for competition, without the glucose spike of classic sugar.
Choose foods made with carbohydrates that increase blood glucose slowly, and minimise your classic sugar intake, for a slower and steadier energy release.
Swap out classic sugar in caffeinated drinks for an alternative using Dr Coy’s sugars.
Galactose is the one Dr Coy points to for oxidative metabolism, because it forces the mitochondria to work and produces only a small rise in blood glucose.

Our recipes page is packed with ideas for incorporating Dr Coy’s sugars into your diet.

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Training the metabolism, not just the muscle

Dr Coy’s work with Dr Thomas May, published in Medical Sports Network, sets out an idea that sits alongside physical training rather than replacing it. The body can be taught which fuel to reach for, and the way to teach it is through what the athlete eats and when.
The body has two ways of releasing energy. The aerobic pathway uses oxygen in the mitochondria and can extract energy from carbohydrate, protein and fat. The fermenting pathway works without oxygen, runs only on carbohydrate, and produces lactic acid. Fermentation is roughly twice as fast, which is why it exists, but it cannot be sustained.

Which pathway an athlete can call on, and how readily, is partly trainable. Dr Coy’s research describes two mechanisms. The enzymes that let the body manufacture its own glucose from amino acids and from the glycerol in fat are only produced when the body actually needs them. Eat plenty of carbohydrate all the time and those enzymes are never made, because there is no call for them. Restrict carbohydrate in phases and the body builds them.
The practical form this takes is simple. Reduce carbohydrate in the evening, then do moderate aerobic work the following morning before breakfast, with the glycogen stores low. With no glucose available to release, the body has no option but to optimise everything involved in burning fat through the mitochondria. Dr Coy notes this does not need to be done every day. Phases of it, repeated, are what builds the capacity.

His conclusion is that an athlete who has trained this way can refill their glycogen stores before competition and still carry the advantage, because the body rebuilds those stores faster and copes better with the phases of an event where the stores run low.

Evening carbohydrates and overnight recovery

There is a second reason Dr Coy’s research points to low glycaemic carbohydrate in the evening, and it concerns recovery rather than performance.

A high carbohydrate dinner produces a large insulin release. Insulin and growth hormone are both growth-promoting, but they do not act together: while insulin is high, growth hormone stays low. Eating carbohydrate with a low glycaemic index in the evening, or simply reducing the amount, means less insulin, and growth hormone rises earlier in the night.

Dr Coy concludes that this matters because growth hormone is the one doing most of the repair work. A high carbohydrate evening meal promotes the conversion of carbohydrate into fat. A low insulin evening allows the higher growth hormone levels that support recovery and muscle growth.

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