Running on Fat …

Back in my marathon days (30+ years ago) I remember reading a prediction that it wouldn’t be long before women were beating the men over the magic distance of 26.2 miles. The logic was very simple, fat is an excellent fuel, fit women athletes carry more fat than fit men athletes therefore women would be better over long distances than men once they matched the men in training.

So far it hasn’t happened, fastest man – Eliud Kipchoge of Kenya 2:01:39 fastest woman Brigid Kosgei also from Kenya 2:14:04. Getting on for 10% slower.

At about 9 calories per gram fat is an excellent fuel trouble is for endurance sports the body is very happy burning glucose and glycogen even though they pack only 4 calories per gram. Stores of glycogen exist in muscle and in the liver amounting to about 600 grams. In ball park figures that’s about 2400 calories for a marathon requiring about 2600. A runner can expect to absorb 50 to 60 grams of glucose from the gut per hour which easily makes up the shortfall.

So fat burning doesn’t really get into the equation during an elite marathon. If it did even the thinnest male athlete has enough fat to go the distance.

Glycogen is king. Glycogen replenishment happens faster after a carbohydrate rich meal. What are the implications for the athlete following a keto diet? Depends who you ask. According to Harvey, Holcomb & Kolwicz the keto athlete is operating at a distinct disadvantage although it is an excellent diet for weight loss.

Dr Caryn Zinn on the other hand is more optimistic …

while Professor Asker Jeukendrup sums up what is known but leaves the question open. That article is well worth reading.

Fat oxidation rates are on average 0.5 grams per min at the optimal exercise intensity. So in order to oxidise 1kg of fat mass, more than 33 hours of exercise is required! Walking or running exercise around 50-65% of VO2max seems to be an optimal intensity to oxidise fat. The duration of exercise, however, plays a crucial role, with an increasing importance of fat oxidation with longer exercise.

There is no doubt that the reforming couch potato can successfully lose weight and burn fat at moderate rates of exercise on a keto diet. Fat around the middle is as much a handicap as lead in the saddle bags. VO2max is the upper limit of your ability to burn fuel a good measure of your fitness. More precisely it’s milliliters of oxygen consumed in one minute, per kilogram of body weight (mL/kg/min) at sustained maximum effort. In other words get the kilograms down and the VO2max goes up without any extra training.

Metabolic Syndrome …

  • High blood pressure
  • High blood glucose
  • Excess fat around the waist
  • Raised cholesterol
  • Raised triglycerides

If you have any three of these you are in the gun. Your risks of type 2 diabetes and heart disease are higher.

Syndromes are not diseases they are clusters of signs that have a high chance of occurring together. Presumably there is an underlying cause but it may not be obvious. In this instance, though, your money would be pretty safe on insulin resistance.

According to the Mayo Clinic website if you have any one of these it’s time to see your doctor. They go on to say …

  • Metabolic syndrome is increasingly common, and up to one-third of U.S. adults have it. If you have metabolic syndrome or any of its components, aggressive lifestyle changes can delay or even prevent the development of serious health problems.

My score is one out of five. I have seen the doctor. The aggressive life style change is underway. You didn’t think I was just writing this for your benefit, did you?

When I look in the bathroom mirror my belly doesn’t look too bad. If I turn my head 90 degrees to the right the awful truth is revealed in a mirror in the adjacent walk-in robe. I guess that’s why friends and the ever solicitous Gayle were so keen to get me on the bike. I’m sure they didn’t expect an instant cycling tragic.

I googled “ideal girth” and got the shock of my life. I was quite competitive though. That’s something you can checkout for yourself or leave a mystery.

I then googled “ideal waist size” and found what I wanted. Then I found a tape measure. And then I contemplated my future.

A man’s waist should be no greater than 40 inches or 102 cm. A woman’s should be no more than 35 inches or 89 cm. Oh, the shame … 44 inches.

Armed with that and your height you can get a reasonably close estimate of your percentage of body fat. The theory is <Here> a calculator can be found <Here>. It is a better measure than BMI which suffers from a number of deficiencies. Arnold Schwarzenegger at his peak had a BMI of 34 (or thereabouts, accounts vary). That puts him securely in the obese range (30 – 39.9). Doesn’t look it …

Actually my BMI ain’t that different. Should be OK.

Well no. It’s time for exercise and diet. Which diet?

Why …

What is it that gets a reasonably sane old man and a slightly more sane and somewhat less old woman out of bed and onto their bikes? Lets leave aside, for the moment, full bladders and search deeper. There has been research.

The Sydney 2009 World Masters Games attracted 28,089 participants from 95 countries in 28 events making it the largest sporting competition to that date. Researchers asked them why they did it. You can read the paper <HERE>. 3928 of the athletes gave them answers, males and females being almost equally represented.

The numerous possible answers clustered into four broad responses

  • Health benefit
  • Social enjoyment
  • Personal achievement
  • Psychological benefit

The highest ranked answer overall, ranked 1 among the girls and 3 among the boys was “to socialize with other participants”. One and two among the boys were “to become more physically fit” and “to improve my health” which also ranked well with the girls. Interestingly weight loss and weight control got mentions but did not rank highly. To compete with others was another non contender for chief motivator but was more popular with the boys than the girls.

The conclusion was that if you’re trying to promote sport to a mixed audience stress the social and health benefits, if a male audience then stress the health benefits. Either way lay off the weight issue.

So where do I sit on all that?

In my youth  I tried many sports. When I discovered basketball I was addicted, I just loved doing it. I couldn’t imagine not doing it. I was fiercely competitive, sometimes embarrassingly so. Once that career was done why did I take up running for which I had no special talent and with no prospect of winning a race?

I would certainly have ticked “to become more physically fit” and “to improve my health”. I might have revealed my narcissism with a “to look better.” I would not have given a rat’s arse for “to socialize with other participants”. I was also very conscious in my running days of some spinoff benefits. I enjoyed hiking, skiing and horse riding. I wasn’t in a position to do those sufficiently often that they would keep me fit. Running meant that I was sufficiently fit to enjoy them when the opportunity arose.

Here I am three months into a third phase of sport training, the geriatric phase. My health is the main motivator. Weight is a huge part of that concern. If you ask a bunch of athletes in training if weight motivates them do not be surprised if it’s not a great concern. Most of them don’t have a weight problem. It’s quite a different story if you’re trying to get sedentary folk off their couches . I have a weight problem. You can motivate me with the prospect of weight control especially if it doesn’t involve going hungry.

And fitness, I want to enjoy the rest of my life. I want to be able to climb up from the beach to the car, walk up a hill for the view and lift the grandkids off their feet. There are still spinoffs.