Tag Archive: science

Check your “facts” before you spread them

While this blog is dedicated mostly to weight loss and the science of health and fitness, I sometimes stray from that topic to include some important basics involving any type of science. We’ve all read Tumblr articles that are in direct conflict with each other. For example, how many people have written articles about how important protein is, only to be countered by how protein in high quantities is horrible? If you ever find a new fact and you’re not really sure about it, there’s a lot of ways to fact check.

Let’s break down a theoretical fact.

According to a recent survey, most people prefer cats.

Pretty harmless fact, right? You may personally disagree, or agree, but that’s not the point. How do we break down this fact and see if it’s accurate or not?

1. Where’s it coming from?

Let’s say the person who posted this fact gives us a source and we find that the Cat Lover’s Association did this survey. Right off the bat we can see a conflict of interest. Of course the Cat Lover’s Association is going to find that people prefer cats to dogs. What if the group that funded the survey was Animals of America? Sounds a bit more reasonable, right? Just in case you should search deeper into that organization. Turns out the founder and president of Animals of America is actually a member of the Pretty Persian Club and owns three cat hospitals that are just for felines! Another source of bias. Let’s say the survey was put on by Happy Pet Owners of America. We look into the group and see that it’s run by a mix of cat and dog owners, as well as a fair amount of bird, hedgehog and horse people. Definitely something we can trust more. Apply this to any other fact: who did the study, who are they tied to, and do they have anything to gain/any bias by the results of the survey.

2. How did they do it?

Let’s say this survey was conducted by asking people coming out of a pet store. Seems like a reasonable place to survey people about what kind of pets they like, right? What if the pet store was a pet store that only had cats? What if they asked people coming out of a common grocery store? Take a look at HOW they conducted the survey and see if there’s any bias behind it. Did they ask every person who they saw, or just every other? Women only? Men only? Really break it down and take a look at how they conducted the survey. Surveys that involve polls online can be tricky because not everyone fills them out. This is a huge issue when news stations or TV stations do surveys, because only people who view that station will answer the survey. If Animal Planet does a survey about animals they’ll get different results about certain questions than The Hunting Network.

3. How many people were surveyed?

Let’s say they asked 5 people. 5 people! That’s NOTHING! 3 of those people could have been related and have a lot in common with their preferences. If they asked 5,000 people at 100 stores across the nation you’re going to have a more accurate tally of if people prefer cats or dogs. If surveys have a large amount of people surveyed it’s going to have a wider array of opinions and get a better idea of the “average person.”

4. Where was the survey conducted?

Some surveys are asked in other countries or in certain areas of the country that can give very different answers. For example, in some countries cats are not really “domestic.” People use cats to catch rats, not as a pet. Their opinions on the usefulness of cats may differ from someone who has a lot of birds and sees cats as a threat to the natural environment for the birds. Likewise, people who live near the ocean may answer surveys saying they like seafood best versus people who live very far inland and prefer beef or vegetables. The location of the survey is important.

5. What question was asked?

This is very important! What if the question was, “Do you prefer cats or dogs?” There are only two possible answers to this question. People who prefer anything other than cats or dogs won’t chose the animal they prefer. Here are other questions that could have been asked…

“Are cats your favorite animal?”

“Do you like dogs?”

“Do you think cats are pretty?”

“Do you think cats are useful?”

Sometimes people will ask these questions and come to their own conclusion about it. What does it mean to “prefer” an animal? If people answer that they do, indeed, think cats are useful they may interpret that are “Most people prefer cats.” Others may say, “Most people thought cats were useful” or “People find cats to be able hunters.” Make sure that the question that is asked parallels the conclusion the survey came to.

6. When did the survey take place?

“According to a recent survey…” is very vague. What is recent? 6 months? 1 year? 10 years? A survey that takes place in 1997 may have different results than one taken in the last few weeks, especially when you’re asking questions about technology.

7. Their sources.

Surveys and studies often cite other sources when they submit their papers. Scroll down to the end of the study to see where they got a lot of their research from and ask yourself the above questions.

Now that you know the many ways “facts” can be interpreted, start using this any time you see a new “fact.” This will help you to become informed and allow you to make your own decisions about what you hear or read.

July 4, 2012 Science Read more >

Eating healthy is expensive and not for everyone. Stop saying it is

Normally “Science Sunday” involves a lot of science jargon along the lines of biology, but this Science Sunday is brought to you by another type of science: social science. I was a sociology minor in undergrad and learned a lot about the complex issues regarding class, gender, race, etc. Anyway, that aside, I want to tackle some posts I see on Tumblr that involve pictures showing a bunch of McDonalds food with a price tag on is versus a plate of veggies with a lower price tag on it. Usually this is partnered with some self-serving “EATING HEALTHY IS SO MUCH CHEAPER!” blah blah. Well, it’s not. And it’s not for everyone. Sit down, buckle up, and get ready for some sociology to come atcha.

1. Food Deserts

PBS did a great article on this, but I’ll summarize. In some places in the country there are no grocery stores for 20+ miles. Yep. Some of you will scoff at that, but let’s put that into perspective. You have to pay for gas to make it the 20 miles there (say you get 15 miles/gallon, as some old cars do, that’s over a gallon of gas one way), then allot the time to do it (say it’s a freeway, 60 mph – 20 minutes to get there), you’ll probably have to take the kids with you because you’re going to be gone for over an hour, you get there, buy your stuff (but you’re competing with people all around you within a 20 mile radius where they are also in a food desert) which may be picked over, then head the 1 gallon/20 minutes home with the kids in the car. OR you could roll through the nearest McDonalds that’s about a mile away and buy some stuff off the dollar menu. Most of these places with food deserts are filled with low income families that cannot afford 2 gallons (at $3.25 per gallon) of gas, plus over an hour of travel with all their kids or family members, to travel to a grocery store some 20 miles away when they can get fast food in town. The town mentioned in the article had one convenience store that didn’t sell fruit or vegetables, and had a small quantity of cold cuts.

Moral of the story? Some people just don’t have access to a grocery store, much less fresh fruit and veggies, regardless of how “cheap” you’ve decided they are.

2. Gas and Cars

I touched on this above, but I’ll dive deeper now. America’s fattest county is also America’s poorest county. Poverty may mean different things to different people, but for this it means living below the poverty line set up by the government. Let’s pretend you’re below the poverty line and we’ll prioritize your finances. Roof over your head > bills to ensure water/electric/etc > food for your kids > clothes for yourself and kids > school supplies > car/truck/vehicle. There are a lot of expenses that come well before owning a car or paying for gas. These poor counties have no public transportation. One cannot just “hop on the bus” to get to where they need to go. Ride a bike? 20 miles to the nearest grocery store to buy food for a family of 4? If access to food is more than a certain amount of miles away then it’s considered unreachable. While you may be able to keep your gas tank full, that doesn’t mean others can.

3. Food Stamps and Government Benefits

Never been on food stamps? A cursory look at the list of what’s allowed on food stamps and what is not allowed on food stamps makes it hard to understand how someone can be obese if they’re on this stuff. But, wait, are these foods even ACCESSIBLE to some people? Remember the grocery stores from above? They don’t have some of these “allowed” foods! Most of these people shop at convenience stores, and according to the website, the following things are NOT allowed on food stamps.

Food that will be eaten in the store.

Hot foods.

Hot foods aren’t a problem, but “Food that will be eaten in the store”? So…everything in a convenience store. You see the problem here? It doesn’t help that these same counties lead the nation in reliance on food stamps.

4. Location, Location, Location!

Like I mentioned with the food deserts, where you live dramatically impacts whether or not you have access to certain foods. It also dramatically impacts the cost of your food. So while these little pictures float around showing an avocado for fifty cents, I have to roll my eyes. When I lived on the West coast I could get an avocado out of my backyard, or even go to the Farmers Market and buy one for that much. I now live in the South, and let me tell you, they had 3/$5 the other day and I about shit myself. That is considered extremely cheap. Likewise, I can pick my own blueberries out here (if I drive about an hour) and it may cost me $10 for what would cost $50 on the West coast. Where you live DRAMATICALLY determines the cost of the food. Shopping at Walmart for groceries, for instance, may have cheaper chicken, but they also don’t tend to have your cage free cruelty free skin free chicken that is so cheap at your local Farmers Market. Catching on? Some people don’t have access to some of the amazing food you do.

5. Time

Some people will probably say, “Well, just grow your own food!” Let’s get some advice on how to start growing your own food, say from an organic site?

2. Start small, 25 square feet for example. Find the spot that ideally has sun all year in your yard. If it’s shaded part of the year, that’s OK too. Avoid the area next to buildings or fences because of possible contamination of the soil by paint, heavy metals or chemicals.

Whoa, whoa, whoa! 25 square feet?! If you live in an apartment or government issued housing, that’s no “small” space! Sun all year round? Not near a building? This isn’t sounding promising. What about yield? There’s no way this 25 square foot “small” garden has enough space for an entire family!

This family, however, has it down pat. They grow enough food for their entire family on 1/5th of an acre in Pasadena, CA. Let’s first ignore the advantages of having amazing weather year around (or that solar energy device that isn’t cheap) and look at what the crux of this is: time. They work from sun up to sun down 6 days a week. If you’re a single mother of 2 working more than one job, this isn’t attainable. In fact, if you’re a single person not needing to feed anyone else in your family except yourself with a job, this is still unattainable. Unless your children don’t go to school and you can condemn them to slave labor, still unattainable. What people don’t understand is that time is a variable in eating healthy, one that a lot of people don’t have.

I’ll save this from becoming lengthy and sum it up for you: if you can eat healthy, if you have access to fresh or semi fresh produce, if you’re close to a grocery store or can use public transportation, you are incredibly lucky. You are part of a minority that doesn’t have to worry IF they will eat today, rather, WHAT they will eat. While you may feel self important touting how it’s soooo much cheaper to eat healthy/vegan/vegetarian/dairy free/etc., remember your audience. You’re speaking to the internet, full of people who can afford computers and have public access. You’re ignoring a growing population that is so poor and so cut off from the world because of it they’re getting their meals from a convenience store.

Next time you want to reblog a picture showing how cheap it is to eat healthy, don’t.

July 4, 2012 Myths, Nutrition, Read more >

How do low carbohydrate diets work?

Diets low in carbohydrates, or “low carb diets”, have been making their way back into the mainstream due to special recognition of Keto, Atkins and Paleolithic diet lifestyles. Like all “diets” (by “diet” I do not mean “what I eat every day,” but rather “what I’m doing to lose weight now”) they are not recommended for life. Why? Science 🙂

What is a carbohydrate?

A carbohydrate is a molecule that gives the body energy. Carbohydrates have many different functions, but for the argument of this article: carbohydrates derived from food give our body the energy it needs to function (see: Krebs Cycle). They are broken down into glucose, ketones, etc. for use by the entire body. The brain and neurons can only use glucose and ketones (that can pass the blood brain barrier) from carbohydrates for energy.

How does this apply to my diet?

When a carbohydrate is broken down it is used for energy. The most common form of this is glucose in humans. If your body needs energy, it’s more likely to use the carbohydrates/glucose circulating in your blood first for energy. Secondarily, it moves to your liver to extract stored glucose. Muscles can also access stored glucose in muscle cells. Next it removes stored glucose from fat cells. Lastly, it will enter a state of gluconeogenesis, where it creates glucose from non-carbohydrate sources. This is why carbs give great short term energy. If they’re available and the body needs energy they’ll use them preferentially. Excess carbohydrates that are not used stimulate insulin, which takes that glucose and puts it places in your body, such as your liver and fat cells.

So why are carbs important if we can just get energy from fat or our livers?

Your brain can only use glucose for energy. If your body doesn’t have glucose regularly circulating it has to get it from somewhere. First, it will dip into whatever is stored. Glycogen is the stored form of glucose. Remember how I said extra glucose gets stored? It’s stored as glycogen. If your body needs energy and there’s none there, it opens the cabinets and grabs some glycogen. The first place it gets this from is the liver. Some glycogen is also stored in your muscles so your muscles can have immediate access to it if needed – but ONLY to your muscles.

What happens when you run out of glycogen?

Ever heard of runners “hitting a wall” around mile 20? They’ve used up all of their glycogen. Symptoms include fatigue to the point of almost being unable to move. They have to counteract this by consuming different types of carbohydrates before and during their races.

So now we’re out of glycogen and glucose…what happens?

Your body has to make glucose from somewhere, so it makes it from non-carbohydrate carbon substrates. This creates ketone bodies that must be used for energy instead. Ketone bodies are made from fat during lipolysis, or “fat cutting.” However, the brain cannot use this for energy because ketone bodies cannot cross the blood-brain barrier to feed the brain. Very few ketone bodies do pass and can be used, but not at nearly the high volume of glucose.

What does this has to do with low carb diets?

The idea is that low carb diets decrease your levels of insulin. Since insulin drives glucose into storage cells, you store less fat. Since you have less carbohydrates, when your body needs energy it goes to glycogen in your liver and muscle. When that’s exhausted it has to start looking for other sources of energy. This leads to ketosis, where the body has a high level of ketone bodies. Theoretically, then, if you don’t have carbohydrates (or are low carb) and need energy your body instead burns fat. This is highly debated amongst scientists, as long term studies have shown that after a year on Atkins the average weight loss is 4%.

Is ketosis bad?

This is the big debate. What about cultures that don’t consume a lot of starches, or cultures that are much more active than ours? They spend more time in ketosis than we do. The argument can come from a standpoint of “what is normal?” Some studies have shown that periodic ketosis is normal and may actually have surprising benefits. Others have shown that ketosis predisposes you to heart disease (in this case, high protein diets), liver damage, and other health problems.

What about ketoacidosis? Isn’t that what diabetics get?

Yes. If you have a high level of ketone bodies and your body cannot get rid of them, the blood becomes acidic. This can be fatal. Healthy people with a working pancreas should not have to worry about this – your pancreas secretes enough insulin to prevent this high of a build up. Another concern arises from alcoholics, who dehydrate themselves so much they block the first steps of gluconeogenesis, and then get ketoacidosis. This is not a concern amongst normal, healthy individuals.

So is low-carb good or bad? Effective or not effective?

Calories are king, so avoiding carbohydrates without counting calories will do nothing for your weight loss and may make you feel weak or easily irritated. As for its effectiveness? Here are some studies…

The Effects of Low-Fat and High-Carb diet on the physiological and biochemical indices in healthy youth with different BMIs (no big difference between the two)

Comparison of the Atkins, Zone, Ornish and LEARN diets for change in weight and related risk factors among overweigh premenopausal women (Atkins group lost 4.7 kg in 12 months, Zone lost 1.6 kg, LEARN 2.6 kg and Ornish 2.2 kg)

BUT

Comparison of the Atkins, Ornish, Weight Watchers and Zone diets for weight loss and heart disease reduction (Each popular diet modestly reduced body weight and several cardiac risk factors. OVERALL DIETARY ADHERENCE RATES WERE LOW. Atkins lost 4.8 kg (21 of 40 participants completed) Zone lost 3.2 kg (26 of 40 completed) 3 kg for Weight watchers (26 out of 40 completed) and 3.3 kg for Ornish (20 of 40 completed) )

On the same vein…

Dietary adherence has been implicated as an important factor in the success of dieting strategies

and

Initial 6-month reduction in weight is the main predictor of both long-term retention and success in weight loss. Special attention is needed for women, current smokers and during holidays. Physical activity is associated with subsequent reduction in energy intake.

July 4, 2012 Fat Loss, Nutrition, , , Read more >

How long until my metabolism drops from fasting?

I think I know where this information came from – The Minnesota Starvation Study. Matchstick Molly does a great breakdown of this study, but in essence they took a bunch of middle aged, totally healthy guys and over the course of 6 months studied how they responded to a diet that was 50% of their daily intake needs. Basically, if the men required 2,000 calories a day to survive, they put them on 1,000 calories a day. What did they find? Their metabolism decreased by 40% – something that stayed that way for about 8 weeks after normalizing the diet. But this is a topic for another part of the metabolism series, so we’ll come back to that. This “fact” is talking about fasting after all!

How long does one need to fast before their BMR (basal metabolic rate, i.e. the amount of calories it takes you keep you alive if you lay in bed all day and don’t move) drops?

This study found that after 3 days of starvation (i.e. no food, just water) your metabolic rate INCREASES, in fact by about 1 kJ/minute (1kJ = .239 calories). This study also shows the same thing – 36 hours into the fast the BMR INCREASED, at 72 hours the BMR was about the same as it was 12 hours into the fast.

It’s not all roses and sunshine though – this study took a few healthy weight females and put them on a 48 hours fast, then measured how they responded to refeeding. It showed that 40-90 minutes after being fed after the 48 hour fast their body had a decreased metabolic rate. This means the thermogenic property of food (covered in future articles of this series) wasn’t as high as it was in other people who didn’t fast. Still: no 40% decrease in metabolism after 12 hours of fasting.

When does your BMR decrease, though? I mean, it can’t just rev and rev away, otherwise you’d die ASAP.This study shows an 8% decrease after 74 hours. So it took 3 days of ZERO food for your BMR to drop a measly 8%.

Another study for your reading can be found here. This one found your BMR increases 3.6% after a 48 hour fast. This is old hat now- you guys know this. BMR increases, then decreases after 74 hours by 8%.

Moral of the story? Your BMR will initially increase during the first 3 days of fasting by about 3-4%, then it will decrease 8% after 3 days of fasting.

I’m calling this “40% decrease in metabolism after 12 hours” a big fat FALSE.

July 4, 2012 Metabolism Series, Nutrition, , , Read more >

Do you have to eat every 3-4 hours to increase your metabolism?

This broke my heart, because I am the Queen of eating every few hours. Initially I was really only hungry 3 times a day, but in every magazine I read it said to eat small meals every 3-4 hours. Now I need to eat every few hours or else I feel like I’m starving. But enough about me, let’s talk about how false this is.

This study is my favorite. They took a few obese women and put them on a 1,000 calorie a day diet. Some of the women ate the 1,000 calories in two 500 calorie meals, the other group ate the 1,000 calories split up over the day. What did they find? At the end of 4 weeks the weight loss was the same in the two groups – they lost about the same amount of fat, muscle, etc. They found that the energy expenditure and the diet-induced thermogenesis (what people THINK is an increase in metabolism when you eat multiple times a day) were the same in the two groups. The most interesting part of the study, however, was that after 4 weeks the “nibbling” group had a decrease in sleeping metabolic rate. So the group that ate twice a day had a higher metabolism at night while asleep than the nibbling/grazing group. This study found the exact same thing.

This study takes it a bit further. They looked at it from a weight loss and satiety perspective. Shouldn’t the people who ate multiple times a day be less hungry, and therefore have less Ghrelin, the hormone that stimulates appetite? PYY, the other hormone, does the opposite – it tells you your full. Shouldn’t people who “graze” or “nibble” have more PYY and less Ghrelin during the day? Nope. Both people who ate 3 meals a day and those who ate 3 meals + 3 snacks had the same levels of both hormones. Well, there goes that.

Kinda on the same vein another study looked at how eating 2 meals a day and eating 3 meals a day affected weight loss. Eating 3 meals a day showed an increase in 24h fat oxidation over the 2 meals, but had a lower fat oxidation at breakfast (fat oxidation = breaking down fats in the body into smaller pieces to use for energy). Not surprisingly they found that the people reported feeling more satiated over 24hours with 3 meals a day than 2. However, this differed from the previous study which measured levels of the hormones responsible for these feelings. In this study, they asked the subjects, meaning this finding may be just based on people being used to eating multiple times a day, or the thought of not eating, etc. If you read the conclusion of the study they get all sciencey and brainy on it, I’ll let you make your own decisions.

This study may be where this information of 3-4 hours comes from. It shows that people who nibble/graze have the same level of carbohydrate and fat oxidation during the day. There is no “spike” in metabolism or carb or fat oxidation, it’s pretty much the same all day. People who eat 2/3x a day have peaks, which are compensatory. For example, carbohydrate oxidation is increased after first meal (hearing “breakfast is the most important meal” anyone?) and was decreased over the fasting period (last meal of the night to first meal in the morning). HOWEVER: during the time your carbohydrate oxidation is low, your fat oxidation is HIGH to compensate for energy. So while breakfast proponents tout that your carbohydrate oxidation is low and you need to boost it, they kind of ignore that your fat oxidation is high to compensate. Your body is a well oiled machine guys!

Moral of this story? As long as you eat in a deficit, it doesn’t matter how many times a day you eat. Your metabolism doesn’t “boost” when you eat multiple times a day. Your BMR is your BMR whether you eat 100 calories every 2 hours or a few 500 calorie meals a day. My take? Eat when you’re hungry. It’s a crazy concept, but do it.

July 4, 2012 Metabolism Series, Myths, Nutrition, , Read more >