Tag Archives: obesity

Human Power: That Other Renewable

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Bike-powered peanut sheller and blender

Of all the renewable energy sources available today, one of them is constantly overlooked by modern society. It’s a shame, because this renewable energy is easy to harness, uses little space, and is complementary to wind and solar energy. I am speaking about that other, forgotten renewable: human power.

Using machines like a hand-crank, treadle, or pedal, human labor can be harnessed as mechanical or electrical work. The most common human-powered machine is the bicycle: mechanical work from a pedal is used to turn a wheel, which propels the rider forward. Bicycles, however, are not the only possible human-powered machines. With some clever engineering, human power has been harnessed to crank washing machines, plow fields, and saw wood. A bicycle can even generate electricity if equipped with a generator, voltage regulator, and battery. It can then power light bulbs, flashlights, laptops, and vacuum cleaners.

Hand-cranked and solar flashlight and radio


Hand-cranked red pepper processor

Unlike other renewable energy sources, human power requires active labor. Modern society, with its distaste for exercise in general, rejected human-powered machines for this very reason. That’s a shame, because human-power provides a nice complement to solar technology. Pedal-power can provide a handy back-up to photovoltaic panels on cloudy days. What’s more, pedal power can create short bursts of electricity, in contrast to the steady-stream of low power provided by solar panels.

An illustration involving an LCD monitor can provide perspective. A typical monitor requires around 100W of power to operate. After cloud cover and the earth’s tilt are considered, a photovoltaic panel might produce a power of around 25W/m^2 on average (1). So to power the monitor, we would need 4m^2 of solar panels. It only takes a single stationary bicycle, however, to generate 100W. Space is only needed for the bicycle itself and a few electronics, so the whole system can be contained in around one square meter. A fit cyclist, moreover, can produce even higher rates of sustained power — up to 200W in athletes. As a result, a well-trained cyclist can produce twice the energy of a photovoltaic panel in one-fourth of the space.

Pedal-power is not unreasonably expensive. A stationary unicycle can be built for under $250, and accompanying electronics can be purchased for around $400 (2). The combined total is $650, roughly the cost of similar solar panel installations.

The real cost savings, however, are for appliances that require only mechanical power. When there is no need to purchase expensive electronics, pedal power is clearly cheaper, since these machines can be built using only donated bicycles, spare hardware, and elbow grease. One NGO based in Guatemala, Maya Pedal, has taken discarded bikes and retrofitted them to make useful tools for local farmers. Old bicycles have been used to blend soap, pump water, grind flour, shell peanuts, and thresh grain. Not only has this removed the drudgery of agricultural work, it has also increased the income of local families. These projects promote development without burning extra gasoline or coal, all while recycling old garbage.

The Western world could learn a lesson. We chronically suffer from energy shortages, and we have no lack of people needing exercise. In the United States, more than one in four Americans are obese, and six in ten overweight. Cheap energy has allowed us to live sedentary lifestyles, which shorten our lifespans and waste trillions of dollars on unnecessary healthcare. If couch potatoes were forced to pedal for their television time, the rates of Western diseases — heart attacks, strokes, diabetes, and cancers — would rapidly plummet.

This is much better than going to the gym. Not only does gym membership cost thousands of dollars, but workout machines like treadmills actually waste additional energy to power. The average treadmill consumes 1500W of power — enough power to run 20 laptops. When people drive to the gym, moreover, they further add to greenhouse gas emissions. With human-power, they could instead burn their extra fat for productive purposes. Those calories might as well be used to wash clothes, blend smoothies, and generate electricity. Why not combat global warming while getting in shape?

Pedal-powered washing machine

Whether human power can truly make a difference depends on the efficiency of the exercise machine and the power demanded by your household. The average person can produce around 35-60W of power using a hand-crank, and 100W-120W using pedal power. Cell phones, flashlights, and watches can all be powered by hand-crank, while computers and televisions can be powered by pedals.

This sounds promising — that is, until you consider our monstrous demand for power. A medium-sized, window air conditioner uses around 1000W of power. To supply the energy for just that one AC unit, it would take a team of ten cyclists pedaling at full speed for the entire day. Once you add in laptops, televisions, clothes driers, washing machines, heaters, and light bulbs, human power becomes woefully inadequate. It would take a legion of cyclists to support the typical American home.

Storing generated electricity is a problem as well. Most pedal generators use lead-acid batteries, which store energy for later use. Devices can then be plugged into the battery rather than directly to the exercise machine. This helps avoid the awkward situation of having to simultaneously pedal while using your laptop. But as Low Tech Magazine points out, lead-acid batteries require massive amounts of energy to manufacture. Sulfuric acid can also cause severe burns, and lead can cause birth defects and brain disorders. Even pedal-powered electricity, then, isn’t perfectly green.

This limitation can be largely overcome by simply transmitting work mechanically rather than electrically. One clever hobbyist retrofitted his bicycle to spin washing machines using only pulleys and belts. The Human Powered Home, a compendium of do-it-yourself pedal-powered machines, provides plans for mechanically connect your bicycle to a grain mill, sewing machine, and tool sharpener. With a little ingenuity, the mechanical applications of pedal power are endless.

Pedal-powered jig saw

Despite its flaws, human-powered electricity can still contribute to sustainable living. Every renewable technology has its limitations, and a human-powered generator is no exception. They may not be perfectly green, but neither are solar panels. When used properly, the benefits of renewable, off-grid electricity can outweigh the harm caused by pedal-power electronics.

Generating your own electricity can allow you to live off the land, which dramatically reduces your carbon emissions. One difficulty with living on rural, undeveloped land is the lack of grid electricity. Pedal power, along with photovoltaic panels, can provide electricity without an expensive connection to the utility company. One Laptop Per Child, for instance, has taken advantage of human power to design off-grid laptops. Students in remote villages often lack access to electricity, but one minute on a hand-crank can provide enough energy for ten minutes of laptop use.

Yet the most profound impact of human power is not the generated electricity itself, but rather the conservation ethic it instills. Producing electricity is hard work. When we hook up an appliance to a power outlet, we are blind as to how much energy we are truly wasting. But if we had to pedal forty-five minutes for each hour of television we watched, we would be more conscious about our electricity usage. We would never have to be reminded to turn off our lights or to sleep our computers, and few would dream of using an air conditioner. Ultimately, it’s conservation — in addition to our feet — that will provide us with the power to lower our carbon footprint.

Do-it-yourself bicycle-power plans are the most affordable and have the lowest environmental impact. There are also some commercially-available attachments. They are expensive, however, and may actually waste more energy than they produce. I encourage you to build your own instead.

  1. Sustainability: Energy: Without the Hot Air generously estimates that a solar panel in Britain produces around 22W/m^2 on average. Low-Tech Magazine estimates a power capacity of 100-150W for average cyclists and up to 300W for athletes.
  2. The Pedal Powered Prime Mover is one unicycle designed especially for pedal power. It costs around $100-$250. The exact electronics will vary depending on your needs.
  3. Photo credits: Alan Levine, CC BY. Engineering for Change, CC BY. AIDG, CC BY-NC-SA. AIDG, CC BY-NC-SA. Donkeycart, CC BY-NC. Bruce Turner, CC BY.

Why Don’t I Feel Rich?

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Two years ago, if you had told me that I was fabulously wealthy, I would have laughed. Hsinya and I were mired in student loan debt. As newlyweds, we struggled each month just to pay the rent. At times, we were forced to pay for our tuition and groceries using credit cards. We studied hard, avoided parties, and did our best to live frugally. Still, each year, we kept slinking further into debt. Secretly, I thought of myself as being poor—pity me.

Relatively speaking, I truly was poor when compared to my richer neighbors. My friends were really living it up during college. Their parents paid for their tuition, room, and board. My friends had money to buy expensive clothing, laptops, and cars. They dined out, went on cruises, and studied abroad in luxury. Naturally, I felt justified to consider myself poor.

But that’s the funny thing about living in America. By surrounding myself with other rich people, I got a distorted view of reality.

As I began to learn more about the world, I started to realize how fabulously wealthy I already was. I was not merely comfortable, nor well-to-do, nor even affluent–I was filthy rich. I had been envying others, when all along I had little appreciation for how wealthy I already was.

I never understood what true poverty was. In America, even our poorest citizens are extremely well-off. Someone working for minimum wage can earn around $15,000 per year. According to the Global Rich List, that places him in the top 15th percentile in terms of global wealth. Minimum wage might not sound like a lot, but it’s enough to rent an apartment, to buy food, to get basic healthcare, and to build savings.

But you and I, as tech-savvy minimalists, probably earn far more than minimum wage. Most of us have college degrees, which places us well above the top tenth percentile in terms of wealth. In fact, most middle-class Americans probably fall in the top 1st percentile of wealth. We are incredibly rich people.

If $8/hr is financially equivalent to fabulous riches, how then does the other 90% of the world survive?

As it turns out, two thirds of the world survives on less than $10/day (1). That paltry amount is supposed to pay for all their food, shelter, and clothing needs. I can’t imagine how anyone survives on such a meager income. I’ve had meals where the appetizer alone cost more than $10. Yet the rest of the world somehow manages to get by.

Consider this:

  • As we gripe about minimum wage in America, sweatshop workers in Costa Rica are gladly working for $1/hr. For such great pay, they’re willing to endure grueling conditions to manufacture the clothes that we wear.
  • As we enjoy our latest and greatest electronics, scavengers in India are collecting the obsolete computer parts we throw away. Our e-waste contains valuable metals that they salvage for scrap production. But first, they must burn off the impurities, which exposes them to hazardous mercury fumes on a daily basis.
  • Though we often complain about our food, refugees in Sudan don’t have any choice. Each day, they receive a daily ration of rice and beans, mostly donated through charities. Each entire meal costs only a few cents per person.
  • While America was complaining about rising gasoline prices in the Middle East, the poor in Tunisia were literally setting themselves on fire. In an effort to protest their poverty, they doused themselves with oil and burned themselves to death.

Poverty is very real. We’re only a plane-ticket away from seeing it firsthand.

My life has been amazing. I’ve never once worried about contracting malaria. I’ve never been homeless, nor have I ever feared starvation. For most of my life, I’ve struggled with the reverse problem: excess. As a child, I was morbidly obese. By the time I was 12 years old, I weighed over 215 pounds. I had too much to eat, not too little. I didn’t exercise because I could afford to drive everywhere. Instead of playing sports, I watched TV and played video games inside my enormous house.

I thought I was poor, but I had never seen real poverty. By most global standards, I was actually insanely rich; I just didn’t realize it.

Suddenly, I remembered what Jesus taught.

Do not lay up for yourselves treasures on earth, where moth and rust destroy and where thieves break in and steal, but lay up for yourselves treasures in heaven, where neither moth nor rust destroys and where thieves do not break in and steal. For where your treasure is, there your heart will be also. (Matthew 6:19-21)

This passage does not apply only to those whom we perceive to be rich. It speaks to every Christian in the Western World; we are incredibly rich people. Being rich isn’t a sin, but being ungrateful is. We ought to put our excess money for God’s purposes—for charity, for preaching the Bible, for reaching lost souls, for encouraging the persecuted church. But all too often, we are secretly dissatisfied with the material riches that we have received. Judging by the way we whine about our money, it’s clear our hearts aren’t set on heaven—we’re still stuck on acquiring more earthly treasures.

Each day, I’m presented with two choices.

On one hand, I can ignore what I’ve learned and return to a normal life filled with ungratefulness and envy. After all, thinking about real poverty and true heavenly riches is a tremendous emotional burden. I’d rather just whine about my low salary and the high cost of taxes.

On the other hand, I can be honest with myself. I have been blessed with so many material riches from my heavenly Father. Am I using them for the sake of the Kingdom of God?

  1. According to Global Issues, 80% of humanity lives on less than $10 a day, and almost half the world—over three billion people—live on less than $2.50 a day.
  2. Photo by GlacierTim, CC BY-NC.

How to Eat Healthy in a Food Desert

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Sometimes, it’s hard to eat healthy. In urban neighborhoods and at travel pit-stops, our food choices are often limited. Restaurants often serve nothing but burgers and soda, and groceries often carry more potato chips than fruit. These food deserts—regions with limited fresh food—have spread all across America. It’s made healthy eating hard; and sometimes, near impossible. In fact, food deserts have contributed to our massive obesity crisis. How, then, can we eat healthy when we have no control over our food choices?

With a little resourcefulness, you can often find healthy food items when you’re trapped in a food desert. If you can find a nearby grocery, you can almost certainly build a balanced, healthy meal covering all five food groups. And even when you’re stuck eating at a convenience store, all may not be lost. Your food won’t be gourmet, but at least you won’t have to settle for a greasy burger.

Here are three key strategies:

  • Scout around. There might be a grocery store nearby. You’re much better off eating lunch at a supermarket than at a restaurant or at a gas station. Grocery stores are more likely to carry unprocessed food.
  • Eat whole, unprocessed foods. Processed foods are stripped of their nutrients, and are often bundled with extra fat, sugar, and chemicals. They’re also more expensive.
  • Follow the food pyramid. To eat a balanced diet, you’ll need grains, beans, vegetables, fruits, and dairy (1). If you can’t get all the groups, just do the best you can.

Here are the tactics for each food group:

  • Fruit: Buy fresh, not canned. Don’t get picky about the type of fruit; cheap, common fruits are fine. Oranges, bananas, and apples are packed with fiber and micronutrients like Vitamin C and phytochemicals.
  • Dairy: Get whole or low-fat milk. Stay away from chocolate milk/flavored yogurt products; they’re loaded with sugar and preservatives. It’s much better to drink organic, but conventional milk is acceptable in a pinch.
  • Meat: You don’t need any. Organic meat would be acceptable, but I doubt you’ll find pastured beef in a food desert. To get enough protein, eat some beans and nuts. It should be easy to find a package of peanuts with no additives besides salt. For beans, scavenge for a can with no extra additives like lard: refried beans are fine. Look for a can with a self-opening top, since you probably won’t want to buy a can opener. Beans aren’t glamorous, but they’re lean and jam-packed with protein. Avoid processed beans like baked beans or chili beans.
  • Grains: Stay away from pastries, donuts, and muffins. A loaf of 100% whole wheat bread will give you plenty of energy without excessive sugar or oil. Sometimes, I’ll carry a box of oatmeal with me. Secret tip: If you’re not picky, you don’t need to boil oats in water. I eat them all the time in their raw, dry form.
  • Vegetables: This food group is the hardest of all: I’ve never seen a convenience store carry veggies. However, if you have access to a grocery store, you’ll have plenty to choose from. Any common vegetable will do: carrots, tomatoes, and lettuce are all fine. Buy some bell peppers and cucumbers and wash them in a bathroom sink. Eat them raw. If you buy a salad, throw away the ranch dressing (better yet, return it to the clerk).

Be sure to avoid these common pitfalls:

  • Don’t eat out. By preparing your own meals, you can better control what goes in it.
  • Stay away from brand names. Commercially trademarked “food products,” such as Cheetos or Coca-Cola, are often loaded with harmful additives like corn syrup, sugar, hydrogenated oils, food dyes, and preservatives. They also lack vitamins and minerals.
  • Minimize packaging. Most things packaged in excessive plastic or aluminum aren’t good for you. Unflavored, canned beans or tuna are the only exceptions I can think of.
  • Stay away from conventional meat. In all likelihood, you already eat plenty of meat. Conventional meat products are extremely bad for the environment, and often contains added oils, fats, sugars, and chemicals.
  • Don’t drink sweetened beverages. This includes not only soda, but also fruit juice. Juice is only healthy when you prepare it yourself and don’t discard the fiber. Most commercial juices have tons of added sugar, and virtually all of them discard the natural fiber. Watch out for deceptive labeling–a juice-flavored drink isn’t really juice.
  • Avoid food that never spoils. Fresh food is more nutritious. Food products with a perpetual shelf life–ramen noodles, candy, microwave burritos–are highly processed.

By following my own guidelines, I’ve managed to scrape by in food deserts while traveling. Even when most restaurants were selling junk food, I was able to maintain a healthy weight eating whole-wheat bread and bananas while drinking milk.

Hopefully we’ll have some real alternatives soon. But until then, we need to be resourceful scavengers of the food desert.

How difficult is it for you to get fresh fruits and veggies? How about organic food?

  1. The USDA updated the pyramid; the meat section has been replaced with protein. Protein from beans/nuts, the USDA says, is plenty. Dry beans and peas may be counted as part of the “meat, poultry, fish, dry beans, eggs, and nuts group.”

  2. A group of volunteers from the Brooklyn Food Coalition went around and mapped all the local food sites and what types of fresh food they served. The data is available at their site, Food Census. Let me know if any of you have seen similar done on a national scale; the rest of us could sure use it.