An excellent series on eating - on Slate

Here's an excellent series of posts about the obstacles to eating right, and a particularly good one about inertia:  http://www.slate.com/blogs/blogs/cleanplate/

I'm sure many of us raised in the 70's and 80's ate exactly this way growing up.  My family did!  Until the low-fat craze of the 90's, when low-fat was the only thing worth considering in choosing a food.  What did you eat as a family growing up?

 

Courtesy Summer Tomato  :-)

Is it as simple as 1 pound = 3500 calories for weight loss?

A lot of diet books, health columns, magazines, etc. tout the basic rule that to lose a pound of body weight, you have to burn or "not eat" 3500 calories. That is - it takes a deficit of 3500 calories to lose a pound of body fat.  The SL was watching the Biggest Loser the other day - and the SL saw Jillian pounding this idea into the contestants.  So, is it that simple?  Well - yes and no.  A pound of body fat does contain 3500 calories worth of fat, so in theory if you burn an extra 3500 calories through exercise, you will lose 1 pound. However, your body is a bit more complicated. A bout of exercise will burn calories, and it will also boost your metabolism ever so slightly the rest of the day (you get some bonus burn). Also, other factors affect your metabolism - whether you feel hot or cold, whether you got enough sleep, if you ate breakfast, if you ate too much salt (water weight), etc.
Also, your body is good at compensating for changes. Normal weight folks who overeat for a day or two mysteriously process food without gaining weight (this doesn't last forever - eventually the body adjusts and you start gaining). People who start an exercise routine may inadvertently sit around more the rest of the day - canceling out the exercise efforts. Losing weight is just as much a mental battle as much as a physical battle with yourself. You have to outsmart your own body - and that's the tough part. Counting calories in and calories out can be simultaneously over-obsessive and inadequate at the same time!   

Is it bad to eat red meat?

Mmmm... steaks, burgers, brats, many of us love red meat. For clarity, let's define red meat as beef, bison, venison, pork, pepperoni, salami, and other non-poultry meats. Consumption of red meat has been linked to development of heart disease, high cholesterol, obesity, and even higher cancer risk.  Many folks (mostly women, I've noticed) shun red meat in favor of turkey, chicken, and fish.  Is red meat really so bad?  Well, yes and no.  One of the problems with eating red meat is that Americans tend to eat a bunch of it at once. A big 1/2 pound purger, a 16 oz. steak, 2 brats, a couple bulging tacos, etc. Red meat does contain higher amounts of cholesterol and saturated fats than white meats, and people with heart disease should limit or cut out red meat. However, recent studies have shown that cholesterol and saturated fat in whole cuts of red meats does not  raise blood cholesterol levels as much as we once thought.  Trans fats, found in processed foods and oils, raise cholesterol much more.  Lean cuts of red meat like filet and sirloin contain a large amount of protein, not too much fat, and lots of iron. They also increase satiety and make a meat-lover feel satisfied.  However, processed forms of red meat, like bacon, salami, pepperoni, processed brats, etc. are still linked with heart disease, high cholesterol, and higher cancer risk.  So enjoy a good, juicy steak (6-8 oz.) every now and then, and skip the processed red meats. Be choosy with red meat, and make it the good stuff.       

Why isn't Pluto a planet anymore? -from Jen in Aurora, CO

In 2006 Pluto was officially demoted from planet status to "dwarf planet."  Now our solar system has only 8 planets.  Why?
Well, in 2006 the International Astronomical Union adopted these standards for classification as a planet:

1. is in orbit around the Sun,
2. has sufficient mass to assume hydrostatic equilibrium (a nearly round shape), and
3. has "cleared the neighbourhood" around its orbit

Pluto meets the first two of these criteria, but not the third.  Part of the change came because astronomers have discovered a number of dwarf planets around the same size as Pluto, and they didn't want all of them to be planets.  Pluto has a pretty wacky orbit and is only about 1/5 the size of Earth's moon.  Originally, when Pluto was discovered in 1930, astronomers thought Pluto was bigger than Mercury.  Then in 1978, the discovery of Charon, Pluto's moon, allowed astronomers to recalculate Pluto's mass, and it was much smaller than originally thought.  Basically, if we keep Pluto as a planet, a whole bunch of other dwarf planets have to be planets, too.  Some people think Pluto should be kept a planet for historical reasons. 
Hopefully, in the next decades, we will be able to learn more about planets in other solar systems and many of them will be much more interesting than Pluto.  Actually, we already know of more interesting stuff here in our solar system.  Jupiter's moon Europa is made of a rock core covered in ice, and it is thought that the surface of Europa might obscure a liquid water ocean http://www.solarviews.com/eng/europa.htm
due to the heat produced from shape changing caused by Jupiter's gravitational pull.  Time will tell.  Hopefully someday we'll get a probe on there to drill for water!   

Do you get the same benefit from protein powder that you do from other traditional protein sources? -from Sandra

Excellent question!  Health and fitness magazines are filled with ads for protein powders, shakes, etc. You can buy soy protein, milk protein, whey protein, etc. First off, what is protein and why is it important for health and fitness?  Protein is composed of chains of amino acids, the building blocks of our muscles and tissues. We need to eat protein to rebuild damaged muscles from working out (that's a good thing), maintain muscle mass, and keep our bodies in top health.  Protein is very useful for dieters because protein makes us feel full.  A meal including protein will keep you full much longer than a meal of just carbohydrates - it increases our feeling of satiety because protein takes a longer time to digest.  Great sources of dietary protein include lean meats like poultry, fish, shellfish, extra lean red meats, beans, legumes, nuts, soy, and low-fat dairy products.  So, where does protein powder fit in?  Protein powder is useful for bodybuilders who need to consume a lot of protein to build really big muscles, and it's hard for them to get enough protein without supplementing occasionally.  Protein powder is a supplement, folks, not a substitute!  Though protein powder may contain added vitamins and minerals, it is not a substitute for real food.  Real food contains many beneficial components like vitamins, minerals, fiber, and antioxidants.  It is best to get most of our protein from "real food."  However, protein powder does have its uses.  For example, protein powder can be used to supplement "real food" like breakfast fruit smoothies, instant oatmeal, and other carb-laden food that needs a protein boost to keep you full. The Science Lady likes to take protein powder along while on multi-day backpacking trips, as hiking for 8+ hrs per day requires a lot of protein for muscle recovery, and when you have to carry it all on your back, protein powder helps!
As for choosing a protein powder, just choose one you like that dissolves easily. None of them contain magic, secret ingredients, no matter what the ad says.  Those glossy ads are all designed to sell you a product!  Also, check out this helpful article on About.com about protein powder for more info: http://bodybuilding.about.com/od/bodybuildingfaq/f/protein_drinks.htm  

How can I live the longest life possible? --from Diane in California

You want the directions to the Fountain of Youth, hm?  That has been an obsession of humans probably since we stopped being hunter-gatherers and had enough time to sit around and think about it.  There is no magic formula for living a long life.  Some of that is pre-determined for you by your genes.  For the sake of discussion, we'll say a very long life is over 100 years, a cool, even century.  Reaching an age over 100+ years tends to run in families, and it's common for centenarians to have a sibling (or several siblings) over 100 years old, too.  They are winners of the genetic lottery, and oddly enough people who live to be that old tend to be fairly healthy for their age (a still-sharp mind, mostly independent mobility, and few serious chronic conditions).  What about the rest of us, dealt a normal hand by our genes?
First, let's talk about why we age.  Time is cruel.  The little pockets of progenitor cells that renew our body's cells  (think skin, intestinal linings, brain, etc.) run out, and the rate of renewal slows.  Our cells accumulate DNA mutations over time (see my post about why we get cancer).  Cellular respiration, the process of burning fuel using oxygen, generates free radicals which also damages our cells.  UV radiation from the sun takes its toll.  Slowly, the telomeres (little caps of DNA on the ends of each of our chromosomes) shorten with each cell division, whittling down our life span like sand trickling through an hourglass.  We can slow the process, though.
Researchers have discovered that these habits increase lifespan:
1.  Exercising.  Regular exercisers live longer, perhaps even decades longer than their peers.
2.  Avoiding smoking and excessive drinking.
3.  Staying active and social, surrounding ourselves with friends and family (the current thinking is that this lowers stress hormones and helps us through tough times).
4.  Not eating too much, and eating mostly healthy food.  
5.  Not being chronically sleep-deprived.  

The longest-lived people in the world are a population of short, petite people living on a Japanese island.  They live their lives with severe calorie restriction, and severe calorie restriction (we're talking maybe 1200 calories a day here, or less) has been shown to dramatically increase life span in lab rats, and correlates with human life span too. Actually, this may be the single best way to live a very long time: eat only enough to barely stay alive. These long-lived Japanese folks exercise a lot (they still farm, and get around by bicycling and walking) and eat mostly vegetables, fish, and rice.  Great foods for long life include fish, green vegetables, olive oil, beans, and eating a mostly plant-based diet.  There are communities of people following this diet now, dedicated to living as long as possible.   
The Science Lady wonders:  is it worth living a long time if you have to barely eat anything and never drink too much?  The Science Lady will stick to the more moderate steps 1-4 above, and hope that her genetic lottery number comes up. 

What is the point of absolute zero? Why do we even have such a term? - from Jen in Aurora

Thanks Jen, for another great question!  See, folks, follow her example and write in some more!  The Science Lady is super excited about such a science-y question. Absolute zero is defined as 0 Kelvin (K), −273.15°C, or −459.67°F.  That is cold!!!  Scientists have never been able to cool anything down to this temperature, ever. For reference, if you've ever seen or played with dry ice before (solid CO2), dry ice is at −78.5 °C. So what is the point of absolute zero?  It actually is important!  It is the reference point from which all other temperature is measured.  It is the reference point and baseline for thermodynamic tables and psychometric charts (think refrigeration, heating, cooling, distillation, chemical reactions, etc.).  It is the zero point in thousands of scientific equations and allows us to explain thermodynamic phenomena mathematically. So, it is mathematically required.  "Yawn," you say?  Well, absolute zero is the point at which matter loses all thermal energy, and atoms cease to vibrate. Weird stuff happens near absolute zero. For example, the boiling point of liquid helium is only about 4 Kelvin (depends on the atmospheric pressure)! Liquid helium is used to chill super-conducting magnets, such as those used in nuclear magnetic resonance (NMR) and fancy particle accelerators.  Liquid helium allows scientists to smash particles together, and study cool stuff like quarks, dark matter, and teleportation (for real! seriously!).  If you were an electron, you could say "Beam me up, Scottie!"  http://focus.aps.org/story/v13/st6  Though we will probably never be able to achieve absolute zero on Earth, some scientists would like to try it in space.  Perhaps someday.  Just because we can't see or feel something does not make it unnecessary.  For example, we cannot accelerate anything to the speed of light (299,792,458 meters per second, or approximately 186,282 miles per second) because the force required to accelerate an object becomes infinitely huge as you approach the speed of light. However, we use the speed of light to calculate the distance between us and other planets, or us and other galaxies.  Fun fact: In February 2003, the Boomerang Nebula was observed to have been releasing gases at a speed of 500,000 km/h (over 300,000 mph) for the last 1,500 years. This has cooled it down to approximately 1 K, as deduced by astronomical observation. This is the lowest natural temperature ever recorded!     

Does the Atkins diet really work? - from Kathy in Washington

Ah yes, the forever changing field of fad diets.  To be fair, Atkins has been around a long time, so it has transcended the label of "fad diet."  The Atkins diet involves eating very little if any carbohydrates, your diet consists only of fat and protein.  That means no starchy vegetables (like beans, carrots, potatoes, corn, etc.), no bread, no pasta, almost no fruit (there are a very few fruits that are ok). The hard core Atkins diet requires the dieter to eat meat, cheese, and low-starch vegetables only. Here's the thing: the Atkins diet really does work, at least in the short term.  It is the most effective diet to lose weight fast. Basically, cutting carbohydrates out of your diet lowers your overall caloric intake, and it also requires your body to start processing fat. Your brain requires carbohydrates to work, so your liver will "produce" carbohydrates from your body's stores and food for your brain's use.  Your liver will also burn stored fat to make up for the calorie deficiency, hence weight loss.  So, if you want to drop 10-20 pounds quick (like for a wedding, or a vacation, or seeing your ex at an event), Atkins is the way to do it.  There is a catch though: it doesn't work for the long term. #1: Almost no one can stand not eating carbs forever. No cookies, no cake, no pasta, no bread, nothing!  Not even most fruits! Even the most staunch dieter will crack eventually, and probably go overboard on a carb binge.  It is a very one-sided diet, and those never work forever. #2:  It is really hard on your liver.  Your poor liver has to make sugar/carbs for your brain, and also process the fat/protein you eat, and also burn your stored fat.  Long-term Atkins dieters show liver stress, which can hurt your liver function long-term.  #3: You might have a fuzzy brain.  Your brain requires glucose (sugar) to function, and some people on the Atkins diet report sleepiness, forgetfulness, and difficulty in focusing/paying attention. #4:  It is hard to be on the Atkins diet. Your friends get sick of your diet restrictions, your family gets sick of it, and while traveling it is really hard to adhere to the diet.
So, Atkins is great for quick trim-ups, not so good for long-term weight loss!    
Another diet that works almost as fast as Atkins but moderates more for the long-term is the South Beach Diet.  It starts out for 2 weeks like Atkins, but then loosens up a bit.