Healthy weight and mathematics

Maintaining a healthy body weight is a simple matter of mathematics. If your energy intake is higher than your energy output, you’ll gain weight, and if you use more energy than you eat, you’ll lose weight.

Energy in = Energy Out

As simple as that!

Pffft – yeah, right!

Our bodies are burning energy even when we are doing nothing, and because we have not mastered the art of photosynthesis, that energy must come from food. If you eat more food and hence consume more energy than you need, you will store the excess as fatty tissue. It’s not rocket science, even if it is maths!

This not-so-tricky maths gets in the way of things! As is the case with most people, I like eating! I’d like to be able to eat more and maintain a healthy body weight. To do this, I need to use more energy.

Is there a way I can increase my energy expenditure without noticing it?

Our energy use is divided into three components:

Basal Metabolic Rate or BMR. This is the energy we use merely being alive. It is the amount of energy we use when we are at rest, after just waking up and with an empty belly. It accounts for around 60% of the energy sedentary people use each day. BMR is influenced by gender, age, and body mass. Essentially the bigger you are the more energy you need to keep your body idling. The older you get, the less energy you use. (So if your a little old(er) lady like me you’re not burning up much!)
Thermic Effect of Food or TEF is the extra energy we need to digest and absorb our food. It takes energy to break down the food in our digestive system and get it into our bloodstream. TEF is a bit like a service fee. The energy in our food needs to be converted into the type of energy our body can use, and this comes at a cost. It turns out that protein needs more energy to be converted into usable energy. TEF accounts for around 10 – 15% of our average daily energy expenditure.
Activity Thermogenesis (AT) is the energy used up in moving around and is further broken into two categories.
1. 1. Exercise-related activity thermogenesis is the energy we use in deliberate exercise such as going to the gym, running, lifting weights, etc.
  2. Non-exercise activity thermogenesis or NEAT is the incidental energy we use in walking around, picking up the kettle, sitting, standing, talking, shopping, cooking, doing the housework. The stuff we usually don’t change into active wear for!

We have the power to control activity thermogenesis. Since it makes up between 25 – 30% of the energy a sedentary person uses, it is the pathway to tipping the balance in favour of weight loss or gain.

Let’s pause for a little more maths.

Every day has 24 hours.
Let’s say you sleep for 8 of those hours where you are running on your BMR.
That leaves 16 hours for you to burn up more energy.
You spend one of your 16 waking hours at the gym (or running/swimming/whatever) and the other 15 hours doing the rest of life.
That means only 6% of the time is used for exercise activity thermogenesis! For most people living ordinary urban lives, we sit on our butts for most of the other 15 hours! That means for 94% of our waking hours, we are using low levels of energy.

Can you increase the amount of energy you burn in those other 15 hours?

The solution is self-evident! You have to increase the amount of energy you expend in all activities! Be more active and less sedentary! Easy-peasy-lemon-squeezy!

In real life…not as easy as it sounds.

Life is busy. You can’t spend 5 hours at the gym every day. You have to go to work. You have to get to work, you have to look after your family. You have to DO life. You may not have time to increase your exercise-related activity, but you can increase the amount of energy you expend in non-exercise related activities?

How do you increase NEAT-ness in your life?

Here are a few suggestions. (some more sensible than others!)

Fidget! Fidgeting wastes heaps of energy! Be careful you don’t annoy too many people though.
Don’t sit when you can stand. If you work in an office, get a standing desk.
Don’t stand still if you can fidget or move from side to side or jiggle around on the spot.
Get your smart gadgets to buzz you if you are sitting still for too long.
Walk to the next office to talk to someone rather than ring or email them.
Ditch the remote control. Tape the remote to the TV, so you have to get up to change channels etc.
Don’t sit in front of the telly and do nothing. If you’re going to watch telly – do something! Lie on the floor & do yoga stretches, get some hand weights or resistance bands and do a few (hundred) biceps curls while you’re bingeing on the newest must-watch show. Alternate arms with legs and do some squats, lunges, hopping, hula hooping, etc.
Don’t drive when you can walk or cycle. Pick a minimum distance and walk it. For instance, only drive if your destination is more than 3 km away.
If you do have to drive, there are ways to do a sneaky car workout! It might not use much extra energy, but it’s better than nothing!
Carry heavy things. Carry heavy things further.
Park the car further away from the entrance when you go to the shops
Get off the bus a stop earlier.
Do 50 quick squats/lunges/calf raises while you’re brushing your teeth.
Crank up the tunes while you’re doing the housework and dance like no-one is watching. If you’re doing the housework, probably nobody is watching! Check out these tips for exercises while cleaning. (some are a bit intense!)
Play outdoors with your children/spouse/friends
Take active holidays.
Go for a hike rather than the movies.
Choose more active leisure pursuits. Play tennis, not trivia. Go bowling.
Choose a more active job! A labourer is going to use a lot more energy than an accountant!
Wear fewer clothes and live in a colder climate! If you need to keep yourself warm, you’ll expend more energy.

The bottom line is, just move MORE and move more often.

Just for the record, sitting is NOT the new smoking. Research shows that the increase in mortality brought about by an excessively sedentary life is around 10%. The increase in mortality due to smoking is approximately 80%. So while both are bad for you, sitting is healthy compared to smoking!

Source:

Levin J.A. Non-exercise Activity Thermogenesis. Nutrition Reviews Vol 26 No 1 pp S82-S97

Recycling Humans?

Chemistry as it applies to the human population.

Recent bush fires in Australia have had me thinking down some very black roads. Some related to politics, capitalism and how the world could have been better if we had taken advantage of different “sliding door” moments.

I have reflected on climate change, sustainability, the death of native animals, destruction of houses and communities. I thought about the moments in history which have led us here to this time and place.

…And then I got to thinking about thermodynamics. About available energy and matter. The fact that there is a finite number of atoms on this Earth.

The big question in my mind then became “How many people could live on this planet without ruining it?”

As a chemist, I have studied closed system reactions. Our earth is essentially a closed system. A closed system only has a certain number of atoms available so once you use them up the reactions have to stop. Rearranging atoms usually uses up energy. Energy is also limited.

These limited atoms are used to make up all the things on Earth including humans. There are an estimated 7,656 million people on the planet. Let’s say the average mass of a human is around 80kg. That’s 612,480 million kilograms of humans. (1 kilo = 2.2 lbs)

If we wind back the clock just 300 years to the 1700s, the estimated upper limit[1] of the human population was 680 million. That means there is an extra 558,080 million (558,080,000,000) kg of human flesh on the planet now compared to then.

Most of those extra kilograms have come from other living things in our closed system because we eat them. There has to be a time when we simply run out of atoms and energy to keep making more humans. The majority of the energy we are using now has come from the stored energy of ancient living things – a.k.a fossil fuel.

While some of the atoms in current humans may have come from recycled humans (i.e. the return of nutrients to the soil through decomposition) most of the time we don’t generally “recycle” humans. We put them in sealed boxes in burial grounds off-limits to agriculture where the nutrients can not be returned to the system. Cremation adds to the carbon in the air.

We waste and misuse so many resources. As consumers, we salve our conscious with the catch-cry, reduce-reuse-recycle, but that is unlikely to be enough to stop or reverse climate change.

Is it time to stop being humans who recycle to humans who are recycled?

Is it time to start thinking about burial practices so the nutrients in humans are available for other uses? I’m of course not the only one thinking about this sort of thing; burial trees pods have been mooted for a while.

It’s all sounding like Soylent Green may not be such a bad idea after all! By the way, that movie, where people were recycled to make food for other humans was set in 2022.

I also believe that those of us in developed economies, who use a lot of resources, have a moral imperative to reduce the number of children we have. We need to seriously consider limiting our population through natural attrition so that some of the atoms can be returned to make other things.

Instead of “one [child] for mum, one for dad and one for the country” how about just one for the planet?

[1] https://www.ecology.com/population-estimates-year-2050/

School Excursion to the Great Barrier Reef.

As a high school teacher, my workday revolves around the trials and tribulations of teenagers and as I have said before it’s never dull! Some days are better than others, and in early December, I went on a Marine Studies excursion to Cairns – the Gateway to the Great Barrier Reef – with forty-two 15-16-year-olds and 3 other teachers besides myself.

Sounds like fun, heh? Well, it was!

The bulk of the trip was managed by Small World Journeys, an Australian based educational adventure provider. They looked after the itinerary, accommodation, most of the meals, and transfers while in Cairns. We organised our own transport to and from school to the airport and the meals not covered in the package. (One dinner, one lunch). We were, of course, responsible for supervising the kids and making sure they were safely in the right place at the right time for the 4-day adventure. The study tour included serious educational content with presentations from marine biologists balanced by hands-on activities including snorkelling at Fitzroy Island and Moore Reef.

On arrival, the weather came as a bit of a shock to the students! I am not sure what they had expected, but the 2000 km plane ride had taken us out of the subtropics to well north of the Tropic Of Capricorn. When we left Sydney, it was only 16ºC with low humidity. When we walked out of Cairns Airport, we were hit by a wall of heat and humidity. (34ºC and 69% RH) and some of them started to melt.

students sitting in a lecture hall — Learning about deadly critters from a PhD student

Our first visit was to the marine research labs at James Cook University. Here we learnt about the myriad of toxic, deadly and dangerous critters found in this part of the world, including brown snakes, cone snails, box jellyfish, Irukandji jellyfish, stonefish, the blue-ringed octopus and to top it off large salt-water crocodiles!

The second day had us at the Reef Fleet Terminal at 9:00 AM for a day trip out to Fitzroy Island to visit the Turtle Rehabilitation Centre, snorkel and to do some mapping activities.

4 girls wearing full body stinger suits getting ready to enter the water — At this time of year, stinger suits are a MUST!

Day 3 was the highlight for both myself and the students with a trip to the Outer Reef. We were booked on a Sunlover Reef Cruise, and after 2 hours cruising, we pulled up alongside their Moore Reef Pontoon. On the way, we listened to Pablo, a marine biologist, explain what activities we would be doing and the tasks we needed to complete.

The students participated in two citizen science projects involving surveying designated areas for species abundance and coral cover and condition. Once back on the catamaran, their findings were uploaded to the Eye on the Reef database, giving a real sense that they had done something that actually counted.

Green Sea Turtle — This photo was taken by one of my students (Piper) using an iPhone in a waterproof case.

All in all, we had 4 hours on the pontoon and students were able to snorkel and explore for nearly all of that time, either as part of the arranged activity or on their own. A buffet lunch, snorkelling gear and stinger suits were all included.

Small Journeys always include a social justice/sustainability twist to their itineraries so our final day involved a talk from two remote area health workers. These nurses work with patients who travel to Cairns for treatment from very remote areas of far north Queensland and the Torres Strait Islands. These people, often indigenous, suffer from a range of complex health problems which are exacerbated by their remoteness and the long term effects of colonialism and discrimination. Alcoholism, domestic violence and child abuse are all too often part of their daily lives. The students sat quietly reflecting on what they had heard while they made up personal care packs using toiletry and sanitary items donated by the students themselves and other community groups.

Fish swimming near a boat — Through the observation window

We stayed at the Cairns Central YHA, which was comfortable and very centrally located. I am sure the other guests let out a muffled gasp when they saw a swarm of over-excited teenagers descending on the pool area after a hot, sweaty afternoon at the University! The next night we gave the house guests a break by taking our kids to the Cairns Esplanade Lagoon, a large public swimming pool which had plenty of space for everyone!

I would highly recommend Small World Journeys to any school looking for an excursion of this sort. The guides were knowledgeable, friendly and well organised. The price was very reasonable for the inclusions and the provided risk assessment, excellent.

If you were looking to go to Cairns on a family holiday, I would certainly recommend the Sunlover trip. There were plenty of other activities in Cairns, which I did not get an opportunity to visit. If you are not a fan of the heat, you might prefer to go in June or July. According to the Small World Journey’s leader, September is pure bliss. Warm, but not humid and no stingers! I will certainly be looking to go back for another visit without 42 kids in tow. (AND with an underwater camera!)