Once I became fat adapted thanks to a LCHF/Keto lifestyle, I started thinking about how my training and racing would be affected. How could I fuel myself during longer workouts and races without sugar? I was hopeful I could minimize carbohydrate use and get away from anything with sugar (sucrose, glucose, fructose, maltose, dextrose, etc. – the are 56 different terms out there that simply mean sugar!) like gels and chomps. Conventional wisdom tells us that we need dietary sugar to fuel our brain and body. This is not accurate as the body does need glucose, it does not need it to come from food. Glucose can be produced from excess protein thanks to the liver via a process call “gluconeogenesis”. Some will say that this is how lean muscle mass is lost and this may be true if not enough protein is part of the diet. Carbohydrates are not inherently evil and they make up an important part of the diet. I believe it’s been the over consumption of highly processed carbs that has led to the obesity and diabetes epidemics . A great source of dietary carbohydrates are green leafy vegetables and I keep sugar, grains, and starch to a minimum but are still part of my diet. Basically, just eat real food.
In fact there are no essential carbohydrates ie humans can live on zero carbs. Not suggesting this, just realize that when you eat a carbohydrate (essentially glucose) the pancreas releases insulin to process it. Insulin will place glucose into the tissues as required and place any excess into the fat cells. This is why insulin is referred to as the “fat storage hormone “. Athletes that rely on carbohydrates to fuel their workouts may need to ingest about 200 to 300 calories an hour. If their glycogen stores become depleted a glucose craving brain can “bonk” and athletes may become confused, nauseous, and even pass out. Some athletes experience issues with their GI tracks and have “stomach” issues consuming high volumes of sugar during a race. Once successfully fat adapted, athletes benefit from metabolic flexibility and are essentially bonk proof. The abundant fat stores that even the skinniest people have can be used to fuel the brain and muscles. The human body can store 1500 to 2000 calories of energy from carbohydrates which may last a couple of hours before refuelling is necessary. A fat burner has 20,000 to 40,000 calories stored in their adipose tissue which equates to almost unlimited fuel. A cool analogy here is to picture a fuel tanker truck pulling a few tonnes of diesel but the engine uses only a relatively small amount of gasoline. The truck has to stop and refuel every few hundred miles even though if it could tap into the diesel it’s carrying, the truck could go for days without stopping for fuel.
Ketones are produced in the liver when glucose is depleted or absent. The body uses alcohol first then glucose (carbohydrates) then protein then fat (ketones). Think of carbohydrates as kindling and fat as a large log. Kindling is used to start the fire, it burns hot and dirty but doesn’t last long. Now add a big log onto the fire and it will burn for a long time providing clean even heat. The liver converts fat cells to ketones which fuel the brain and body and this is the basis of a Ketogenic diet. Ketones have been shown to be a superior fuel to glucose leading to higher energy levels and better brain function. I know that this will be hard for some to understand as the “we need sugar to survive” dogma has been around since the late 70’s when we were told to avoid fat. Remember that sugar has zero nutritional value and simply provides fast, short lived energy. Anyone can find proof for whatever they want to believe but if you research with an open mind you might be surprised at what the latest science is saying.
Would humans have been able to survive without an ability to hunt and gather on an empty stomach, essentially in a fasted state (Ketosis)? Being able to use stored fat was critical to our survival. I think it’s obvious that fat is stored to keep us alive when food is scarce or unavailable. Ever wonder how a bear is able to sleep thru winter without food? Bears fill up on berries (carbohydrate) in the fall which puts them in fat storage mode. This enables the bear to fatten up so it can survive the winter without eating. Without the ability to function in a fasted state we would have died off as a species millions of years ago. In this day and age food is plentiful and we never need worry about our next meal. I would say that constant eating and snacking are not a normal way for humans to replenish energy stores.
Rick Keto Ironman 