How squinting helps us see

About squinting: to see that "squishing the eyeball" is not an important factor, someone can try making a "lens" out of a sheet of paper with a tiny hole punched in it (for example, by a pin). That actually works to improve the vision of nearsighted people like me (I don't know about far-sighted people).

Re: "Dieting doesn't work anyway".

I feel like that can't possibly be literally true.

I understand that eating less can change your metabolism, or can have other undesirable side-effects (such as causing a lack of muscle mass, for example).

However, if the number of calories you consume is less than the number that you burn, then you will lose weight. There is no other way around it without violating conservation of energy.

Regarding pinholes, I'm nearsighted enough without glasses that the digital clock across our family room is just a blur. If I'm taking a short snooze (sans glasses), I'll make a really, reeeaaaally, tiny "OK" symbol with my hand and hold it up to my eye. With a little adjustment I can then make out the digits on the clock.

Re: "Dieting doesn't work anyway".

I feel like that can't possibly be literally true

I agree with you. It seems like we always get this sort of article this time of year. But many people can and do lose weight permanently. My father in law was dangerously overweight, adopted a rigorous diet and exercise program, and has been a healthy weight for over 20 years.

OTOH, most people don't succeed in dieting, which is really what the article is saying. They end up gaining the weight they lose back, and the net result is probably more harmful than not dieting at all.

Whether we should ever try to lose weight, however, probably isn't a question for psychologists. It's probably more of a philosophical question than anything else.

Are you discounting the pinhole effect from squinting? I have to force myself not to squint when taking eye exams because the whole point, of course, is to measure my vision. ("It's not a contest, you idiot," I tell myself.) But squinting in a dark room does help me to see the vision chart. I attribute this to the pinhole effect, not to excluding peripheral light, since there is essentially none.

I believe the pinhole effect is the same thing as squinting. Effectively, you're increasing depth of field by decreasing aperture size. You're using a smaller, more forgiving part of your lens to focus.

A pinhole lens works (that is, focuses essentially from the front of the "lens" to infinity) because it limits the solid angle from which rays of light from a particular point in space can reach the detecting surface (the back of the eye). There is some fuzziness related to competing effects from the geometric optics of the pinhole itself (smaller is better), from diffraction (smaller is worse), and from reduction in intensity of the light (smaller is worse). The pinhole lens in front of the eye helps you to see more clearly because the eye is essentially relieved from focusing.

I just posted an article giving what I hope is a helpful discussion of why pinholes help.

The idea that absolute calorie intake minus calories expended is meaningful is simply wrong. I have two examples where this failed.

I met a woman years ago who was grossly overweight. About five feet tall, and over four hundred pounds. She looked for a diet where she could maintain her weight. She gained weight on a 700 calorie diet. She was quite active, and, no, evidence suggests that she did not cheat. Finally, she was able to maintain her weight on a 500 calorie diet. Once stable for a year, she underwent surgery to remove some 190 pounds. Still a bit chubby. Most people would not survive long term on 500 calories.

When i was in school, i ran cross country. My workouts were 15 miles, twice a day. That's 30 miles a day. 210 miles a week. 14 weeks. My calorie intake was not measured precisely, but did not increase. It was probably around 2500 calories. According to Dr. Cooper, my calorie expenditure was over 4000 calories per day. I should have lost weight, right? The actual result was a 10 pound weight gain.

One reason my intake did not increase was that i could not afford to eat more. The cafeteria provided "all you can eat", but my runs ran into both breakfast and dinner. The result was that they closed just a minute or two after i arrived, every day. So, no seconds.

Absolute calorie figures do not seem to understand how physiology really works. One summer, i decided to bicycle to work. (My new job had showers). When i started, my average speed was under ten miles per hour. At the end of the summer my average speed was 21 miles per hour. At these speeds, drag increases with the cube of the speed. So, a doubling in speed requires an eight fold increase in power. To achieve this, one's cardiovascular system needs to adapt. It does this by increasing efficiency and by increasing capacity. But base efficiency of physiology across a population behaves with a bell curve distribution. There are going to be outliers, like the woman i met above.

What does work is relative lifestyle changes. Eat a little less. Exercise a little more.

These aren't many data points, but in the grand tradition of physics, i'm more than willing to fit a ninth order polynomial to them.

Stephen, it may be that the estimates for how many calories are to be found in various foods are wrong, and it may be that the estimates for how many calories are expended doing various exercises are wrong. But what I'm claiming is that nobody is expending more energy than they are intaking from their food. That would violate conservation of energy. If you actually get 4000 calories of work out of 2500 calories of food, then you are a perpetual motion machine, and the energy crisis is solved.

The conclusion that "mass dieting" doesn't work never seems to be based on an observation in which the "dieting" was controlled. Effective dieting combined with effective exercise DOES work. But we're not talking about trying Atkins for a few weeks or making a resolution to take up jogging. We're talking about weeks or months of trial and error to find the calorie deficit right for YOU, measuring food to the quarter ounce, counting macronutrients to the gram, cycling calories and carbs on a weekly basis, eating supplements, and using the right combination of challenging physical exercise to which your body does not adapt (i.e. high-intensity interval training as opposed to "slow and steady" cardio, and lifting increasingly heavy weights).

Body builders do it all the time. Over and over. They eat to gain fat + muscle, then effectively diet down to extremely low levels of body fat for competitions. This is not "casual" dieting, and that's why it works. These articles should specify that they are talking about casual, uncontrolled, self-reported and most likely ineffective "dieting" behavior. Easy dieting may not work but hard dieting does.

I discovered the pinhole camera when I was about 4, using a curled up finger. I was severely nearsighted back then, and the trick allowed me to see things above my reach for the first time in my life (solving mysteries like 'What is that thing up there?').

I rediscovered it around age 10 when I looked closely -- back when my eye would focus at something an inch away -- at construction paper, finding that the point of a thumbtack was a chisel in shape because it made a square hole when pushed only a little bit in. Then I compared round holes to square holes and found I could see better through the round hole. Grownups could not explain why. Neither could my teacher.