Archive for the ‘Science’ Category

Can Artificial Sweeteners Make You Gain Weight?

February 12, 2008

Psychologists Susan Swithers and Terry Davidson at Purdue University reported today in the journal Behavioral Neuroscience that a study they did on rats showed that those fed yogurt sweetened with saccharin gained more weight than those fed yogurt sweetened with sugar. The rats fed saccharine ate more, presumably because the sweetness of the saccharine stimulated their taste buds to tell their brains to signal their stomachs to expect more calories in the form of sugar than they actually received.

When I first heard this on MSNBC today, I thought that the network covered this story in a silly fashion since they jumped from reporting the results about saccharine fed to rats to asking whether the drinking diet soda or eating other foods that are artificially sweetened might cause weight gain in humans.  I found this silly because my immediate reaction was to think that humans who drink and eat foods with sugar substitutes are doing so intentionally because they want to either lose weight or avoid gaining weight; in contrast the rats had no such goals and presumably ate until they felt satisfied.  My attitude was that people would apply some will power and resist the urge to eat more regardless of any crossed wires between their brains and their stomachs.  I suppose I wasn’t really being realistic.  If people had as much will power as I was supposing, we wouldn’t have so many obese people here in the United States.

One thing MSNBC had failed to mention which Scientific American’s website did was that Dr. Swithers and Dr. Davidson pointed out that their results are in line with recent studies in people that demonstrate that people who consume diet soda are more susceptible to a collection of risk factors for heart disease and diabetes known as metabolic syndrome.  For instance, a paper published in the America Heart Association’s journal, Circulation, indicated that the risk of developing metabolic syndrome was 34% higher for people who drank one can of diet soda each day.  So, there actually is some evidence to suggest that the findings in rats might also hold true in people.

I think it would be interesting for the scientists to study how rats and people respond if fed various mixtures of sugar and saccharine or other artificial sweeteners.  When I drink diet soda, I usually drink it with something else, sometimes even with cookies or other sweet foods that contain sugar.  I drink diet soda rather than regular soda because I actually like the bitter nuance of aspartame in diet soda and figure that I don’t need the extra calories that regular soda would have.  In contrast, I don’t really like low-fat or artificially sweetened cookies.  Assuming the aspartame on my taste buds does send some signal to my brain saying that my stomach is going to receive some sugar, is the amount of sugar in the cookies or other food sufficient to meet my stomach’s expectations?  Or would the brain still perceive a shortfall of sugar in comparison to its expecations?

Along these lines, I wonder if the observed linkage between diet soda and metabolic syndrome is primarily driven by drinking diet soda without food — maybe a can of diet soda drunk by itself stimulates hunger that leads to additional eating afterwards.  Determining the exact circumstances under which consumption of artificial sweeteners stimulates extra eating is clearly very important.  Artificial sweeteners clearly have value if people can consume them without being stimulated to eat more than they otherwise would.  If it turns out that artificially sweetened foods should be mixed with regular food to avoid confusing the brain, then it will be important to determine the ideal ratios so that people can then minimize their total caloric consumption.


Basic Science Exam for Presidential Candidates

February 6, 2008

As someone who has studied science and math and remains very interested in them, I am often disappointed that very few questions about science are asked during political debates.  So, I decided to create a  Basic Science Exam that Wolf Blitzer and Brian Williams could ask Presidential candidates in future “Presidential Entrance Exams”.  Ideally, this would be done by having the candidates enter their answers to each question simultaneously on laptops, after which their answers would be revealed to them and the viewers along with the correct answer.  Think how interesting it would be if one candidate got most of the questions right while one got most of them wrong.  Would people really want to vote for a candidate who demonstrated that they were ignorant of the basic science needed to set effective health care, energy, and climate change policies?

Here is my Basic Science Exam for Presidential candidates:

  1. Which of the following is a greenhouse gas that contributes to global warming? a) oxygen, b) methane, c) nitrogen, d) argon
  2. Which kind of fat is widely considered unhealthy to eat in large quantities? a) saturated fat or b) unsaturated fat
  3. Which of the following is a key concept in Darwin’s theory of evolution? a) genetic drift, b) taxonomy, c) acquired characteristics, d) natural selection
  4. Do antibiotics work against viruses? a) yes or b) no
  5. Which hormone is involved in diabetes? a) dopamine, b) insulin, c) melatonin, d) progesterone
  6. Which gas do plants produce during photosynthesis? a) oxygen, b) methane, c) water vapor, d) carbon dioxide
  7. Which of the following would reduce or eliminate CO2 emissions from coal-powered energy plants? a) hydrolysis, b) carbon transmutation, c) carbon sequestration, d) hydrogen synthesis
  8. Which of the following processes powers the Sun and other stars? a) nuclear fusion, b) nuclear fission, c) ionization, d) quantum tunneling
  9. Which of the following could be used as fuel in a nuclear fusion reactor? a) uranium, b) oxygen, c) hydrogen, d) lead
  10. What do photovoltaic cells convert sunlight to? a) heat or b) electricity
  11. Which of the following can contain the other? a) atoms or b) molecules
  12. Can sound be heard in a pure vacuum? a) yes or b) no
  13. Can gravity bend light rays? a) yes or b) no
  14. How old in years do geologists think the Earth is? a) 6,000,  b) 130,000, c) 65,000,000, d) 4,500,000,000
  15. Did humans and dinosaurs ever live on Earth at the same time? a) yes or b) no
  16. How much of the Earth is covered in water? a) 10% b) 25%, c) 50%, d) 75%
  17. Which of the following is true? a) the Earth orbits the Sun or b) the Sun orbits the Earth
  18. Which of the following statements is true? a) The Sun is smaller than the Moon, b) the Sun and the Moon are the same size, or c) The Sun is bigger than the Moon
  19. Which of the following is the universe doing according to astronomic observations? a) contracting, b) expanding, c) staying the same size?
  20. Which of the following is not part of the scientific method? a) observations, b) hypotheses, c) dogmas, d) experiments

I realize it’s highly unlikely that any Presidential candidates would actually agree to take this exam in front of live cameras, but wouldn’t it be great if they did?  Maybe the candidates who made it all the way through the election cycle and ultimately won the general election would then actually understand enough science to make intelligent policy decisions.

Answers to the questions are in the first comment to this post.