Famously, 542 individuals (of 3,711 passengers and crew) on the cruise ship Diamond Princess tested positive for COVID on Feb. 18, 2020. The ship was quarantined, off Yokohama, Japan, until March 1, at which time everyone disembarked and was repatriated to their home country.
Being “trapped” aboard a cruise ship during a pandemic is scary. People began cancelling previously booked cruises. Ships were parked, waiting for a vaccine or treatment to appear.
At that time, the luxury line Seabourn offered attractive fares for future sailings. We booked a two-month cruise, for February and March 2024, from Chile to Florida visiting the Antarctic, the Falkland Islands and the Amazon, on a ship with 450 passengers.
Living in the lap of luxury for an extended period isn’t as easy as you might think. It’s a tough job, but somebody’s got to do it. With Michelin Star cuisine, I was surprised how few of us became tubby. I gained three kilograms (my wife isn’t saying). Restraint was hard; I was brought up to clean my plate. (“It’ll taste better tonight, hot, than cold at breakfast dear.”)
Gaining weight is easy, shedding it isn’t.
In previous columns, I wrote that humans are programmed by evolution to store excess food intake as fat, in preparation for future hunger. Of course, few experience food shortages today.
The only way to lose weight is to eat less than your metabolism requires. Sadly, we react to low food intake by resetting metabolism to an “economode” – another evolutionary adaptation developed millennia ago.
Normally, a man consumes 2,400 kilocalories (kCal) of energy day; a woman 1,800 kCal. In economy mode, our metabolic rate drops by 25 to 30 per cent, to roughly 1,800 kCal for a man and 1,350 kCal for a woman. If we want to lose weight by restricting food intake, we must eat less than that; much easier said than done.
Exercise – an example
If I lost 10 kilograms, I would return to my weight when we moved from Southampton, England to Barrie in 1988. Of course, I want to burn fat, not muscle. This is only possible by adding exercise to my day.
For a man, “hard work” equates to 576 kCal per hour. This is defined as a level of activity which can be sustained for a day, but not every day. However, a one-hour run at 10 km/h would fit into a normal work day and should be doable daily. (Physiology for Sportspeople, Peter Bursztyn, Manchester University Press, 1990).
Fat has an energy value of 9,000 kCal per kilogram. To get rid of 10 kilograms of fat I must “burn” 90,000 kCal. Dividing by 576 kCal comes to 156 days. It will 156 days of running an hour per day to burn off.
Of course, in real life this would take longer. Most of us, particularly those carrying extra weight, could take weeks to get to achieve the necessary physical fitness. Some might never get there – looking in the mirror here.
Raise your metabolic rate
Most people experiencing cold environments have higher metabolic rates than those living in centrally heated houses.
A prime example are the Yaghan people inhabiting the tip of South America. These folk wear little or no clothes despite a cold, rainy climate. Their metabolic rate is 50 to 100 per cent higher than ours. They can afford such a high energy expenditure because their (abundant) diet consists largely of fatty fish.
Korean and Japanese “ama” women dive for shellfish winter and summer in the Sea of Japan. In the 1960s, they wore only loincloths, although now many wear neoprene wet suits.
Summer sea temperatures are 27 C, dropping to 3 C in winter. Ama women’s winter metabolic rate rose 20 per cent above the summer value, despite their diving just 60 to 90 minutes per day. Non-diving neighbours showed no seasonal change. (The Diving Women of Korea and Japan, Suk Hong and Hermann Ranh, Scientific American, 1960).
In experiments exposing Caucasian men to cold stress with minimal clothing, metabolic rate rose to cope. (Adaptation to Thermal Environment, Laurence Mount, Edward Arnold, London, 1979). Caused by shivering and activating a tissue called “brown fat” this boosts metabolism and kept their body temperatures from falling.
People living in very cold environments (Canada’s Inuit, Sweden’s Sami) rely on traditional, superbly designed clothing (furs). This creates a “tropical” microclimate around them so they experience little thermal stress and have metabolic rates like ours. The traditional igloo is superbly wind-proof and surprisingly well insulated – better than the substandard housing the Canadian government builds for them now.
Most animals, humans included, boost metabolic rates to cope with periods of cold. We have beaten cold through technology: central heating, down-filled clothing and car heaters. Our ability to crank up our internal “furnace” is still there.
All it takes is to turn down your thermostat by 1 C and shiver. I recall some research (cannot find it now) showing that men sleeping in plain canvas tents under just a sheet, at near-freezing temperature adapted in one week. Initially, shivering kept them awake, but in several days they just slept through it comfortably.
All you need to do is suffer a little, and your elevated metabolic rate will work 24 hours a day to begin chewing away at your fat stores. No need to “pump iron.” Clearly, the way forward is to reduce food intake, exercise a little and “chill.”
The bottom line
However, to make best use of the above information on exercise, you should understand the basics of metabolism.
“Everything” in our bodies is powered by the molecule ATP (adenosine triphosphate). We keep minimal amounts of ATP on hand – enough for a second or two of hard work. We regenerate ATP quickly from creatine phosphate of which we have 10 seconds worth; just time enough to get anaerobic metabolism moving. That’s how sprint races (100 to 400 metres) are run and we can do this for a minute.
By then we have revved up aerobic metabolism and are burning through our glucose stores.
That’s when we begin to activate fat metabolism – the burning of fat – the true objective of the exercise. It is worth realizing that it takes 30 minutes or so for fat consumption to get rolling. If you exercise for less than 30 minutes, you will have consumed mostly glucose, leaving the lard intact.
No matter how hard you work out, if you don’t last longer than 30 minutes, you will have achieved little. Moreover, if you stop your workout too soon, you may have burned so much glucose that you crave a Mars bar.
Readers who are still awake and alert will realize that the more physically fit you are, the easier it is to exercise long enough to burn fat.
It ain’t fair, truly, but that’s how it is.
Obesity has become a worldwide epidemic, one with real health consequences. These include high blood pressure (leading to stroke), Type 2 diabetes, osteoarthritis (joint disease), cardiovascular disease, liver disease, certain cancers (breast, colon, endometrial), and others.
It is extraordinarily difficult to lose weight, but it is worthwhile. At the minimum, you will be more energetic, better able to walk your dog, enjoy gardening, play golf, climb stairs, etc.
What about fancy diets?
What about those expensive weight loss medications?
Peter Bursztyn is a self-proclaimed “recovering scientist” who has a passion for all things based in science and the environment. The now-retired former university academic has taught and carried out research at universities in Africa, Britain and Canada. As a member of BarrieToday’s community advisory board, he also writes a semi-regular column.
