Plateau …

To recap very briefly … Old couch potato is enticed onto a bicycle and it reawakens something within that has been dormant for quite a few years and he likes it.

The regime goes something like this …

  • cycle 5 days a week – average 250 km/week in recent weeks.
  • weight training 2 days a week.
  • Diet – low carb high fat (keto) ovo-lacto-vegetarian, lunch and evening meal nuts in between (usually no breakfast). Protein supplementation to reach ~1.5g/kg of ideal weight.

No calories have been counted.

Too many progress reports would become boring but not enough could give the impression that I was trying to conceal a failure.

Initially, as always, the weight simply fell off …I weighed myself the day I bought the first bike. The diet started three weeks later. The dots represent every Monday since. Somehow I always seem to weigh more on Mondays than on other days, how does that work? If I changed days would that phenomenon follow me?

About five weeks ago the weight loss ground to a halt. 13 kg of ugly weight gone – a guillotine could not have done better (average weight of a human head is only 5kg). Along with it went more than four inches from my waist.

A successful diet is one where an overweight person intentionally loses more than 10% of their body weight – 11kg of 93 = 12% – and keeps it off for more than a year. The foundational study by Stunkard and McLaren-Hume 1959 found that of 100 obese individuals only 2 were in fact successful.

So this is the time to ponder a few important questions.

  • Why does weight loss stop?
  • What can be done to prevent a big bouncing relapse?

It takes a certain amount of food to maintain a particular weight in the presence of a certain amount of exercise. That’s simple enough but how much varies from person to person and even for one person at different weights. So consider firstly the unlikely case of someone eating the same number of Calories and doing exactly the same amount of work every day. Let’s assume that at the outset Calories in is less than Calories out – the stage is set for weight loss.

There are two forms of energy store in the body glycogen and fat. Glycogen is stored in the liver and muscles.  It is readily available energy, the first to go on a diet and it takes three times its weight of water with it. That’s the easy part. Once we get onto mobilising fat things slow down.

But progress goes on. As weight is lost the energy cost of the work done decreases and the size of the Calorie deficit decreases with it. Weight loss slows and will eventually stop.

In reality it stops well before the point that simple maths predicts for a number of reasons. Humans have not always existed in a world awash with food. We have evolved mechanisms that help us survive food shortages, endure periods of starvation. The recently emptied fat cells pump out lipoprotein lipase, which tells  the brain “hey, we’re starving”. Leptin, the hormone that tells us we have eaten a sufficiency, diminishes. Ghrelin, the hormone that makes your tummy grumble, increases. Peptide tyrosine-tyrosine and cholecystokinine increase. These things conspire to increase your appetite.

Meanwhile the resting metabolic rate goes down in response to reduced thyroid hormone (T3)  and reduced activity in the sympathetic nervous system. Levels of a group of proteins that uncouple metabolism from energy production (analogous to wasting petrol by revving the engine with the clutch disengaged) diminish. In the good times some excess energy was simply turned into heat now faced with a famine nothing is being wasted.

Yet more energy can be saved by reducing nonessential activity.

When the recently obese person is compared to a never obese person of the same weight and body composition their energy economy is quite different. All the differences are to the dieters’ disadvantage. Failure beckons and I’ve traveled that route before.

However, only 98% fail.

So far I’ve relied rather heavily on Exercise Physiology for Health, Fitness and Performance by Sharon Plowman and Denise Smith. The next section owes much to a paper by Wing and Phelan which can be found <HERE>.

They paint a picture that is less bleak, as many as 20% manage to keep the weight off, and they present some of the characteristics of those that do identifying six key strategies for long-term success at weight loss …

  1. engaging in high levels of physical activity;
  2. eating a diet that is low in calories and fat;
  3. eating breakfast;
  4.  self-monitoring weight on a regular basis;
  5. maintaining a consistent eating pattern; and
  6. catching “slips” before they turn into larger regains.

In addition those who initiated weight loss because of a medical trigger such as a relative having a heart attack were more likely to succeed.

Holidays and weekends are dangerous moments and those that maintain the same regime through these periods as they do the rest of the time do best. Once relapse is underway prospects are poor. Depression bodes ill.

I can put a tick against items 1, 4 and 5. Item 6 is really what item 4 is all about and hasn’t yet been put to the test. My most obvious vulnerability is relying on satiety to determine portion size.

But, oh dear, a low fat diet and eating breakfast are not on the agenda.

I have no doubt that these are common practices in those that succeed in long term weight maintenance but my conjecture is that these have not contributed to their success. Clearly these are remarkably self disciplined people. The discipline they have imposed on themselves is a very orthodox one. Dr John Harvey Kellogg told the world that breakfast is the most important meal of the day to the certain benefit of the food producers but there is no evidence that it is to the benefit of the rest of us. On the other hand there is some evidence in favour of intermittent fasting. I tend not to eat after 9pm and defer breakfast until noon giving my pancreas a 15 hour rest on the majority of days.

Fear of fat is another well entrenched orthodoxy. I’ve lost weight on a high fat diet. It defies logic that I can’t maintain weight on a high fat diet.

These two points are examples of well-person confounders – baggage that is carried along with useful characteristics that really do contribute to health.

Or at least I hope that’s the case!

Where Dreams Go To Die …

As mountaineers ascend the world’s highest peaks they know that above 8,000 metres they have entered the death zone. At this level oxygen is so scarce that the human body can no longer acclimatise. Indeed the highest permanent human habitation is a fair bit lower – La Rinconada in the Peruvian Andes at 5,100 meters.

Time in the death zone is at a premium, the climber must achieve their goal and descend. To remain long is to die.

So it is with my weight loss diets. Somewhere between 5,000 and 8,000 grams my body ceases to acclimatise. Progress ceases and the journey downhill begins. The summit beckons, I linger hoping that I will find the strength to continue but alas it was never to be.

In this I am not alone …

A search was conducted for weight-loss-focused randomized clinical trials with >or=1-year follow-up. Eighty studies were identified and are included in the evidence table.

… A mean weight loss of 5 to 8.5 kg (5% to 9%) was observed during the first 6 months from interventions involving a reduced-energy diet and/or weight-loss medications with weight plateaus at approximately 6 months. In studies extending to 48 months, a mean 3 to 6 kg (3% to 6%) of weight loss was maintained with none of the groups experiencing weight regain to baseline. In contrast, advice-only and exercise-alone groups experienced minimal weight loss at any time point.  Franz et al.

I started cycling five months ago. The distance covered each week has slowly increased. Last week it passed 200 km for the first time. The one long ride each week has also increased. The longest so far is 80 km. A kilogram a month melted without conscious dietary modification over the first three months. I have now been on a low carb high fat diet for two months and a further six kilograms have departed.

Is my diet in the death zone?

It doesn’t feel like it. My trousers are walking around looking for a decent bum to fill them, my belt is distraught at the loss of the companion that for so long bore its imprint  but I feel good. Per ardua ad astra. Carpe diem. Et cetera.

The greatest challenge is ahead.

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.

Progress Report …

We are two weeks into the Low Carb diet. Gayle has been cooking up a storm. Some of the food is less than exciting but most is delicious. Some is quite exceptional given the inclusion of previously shunned fats.

We haven’t been able to bring ourselves to eat dead animals so have to be thoughtful about our protein, eggs and cheese are in after that it’s tofu and nuts. Ground linseeds help with the omega 3s. Vitamin B12 comes from a pill.

I was losing weight before starting the diet. Three kilograms in the three months since I bought the bike. Two more kilograms have gone in the past two weeks along with 2 inches off the belly. No cravings, hunger satisfied. Not a calorie has been counted. I’m drinking a lot and peeing a lot, sure signs of ketosis. My confidence is high.

It feels as though athletic performance has suffered a bit, perhaps more for Gayle than me. We have been able to keep up a pretty high volume (by our standards anyway) 343 km in the past 14 days. I skipped this week’s long ride in favour of a more modest distance. I think we are getting through that now as we start to burn fat as our energy source.

Every diet that I’ve tried has worked … for a while. The promise from this one is that it will go on working. We will see.