Thursday, December 22, 2011

F4: Fats for Fighting Fat - Salmon


When it comes to lean protein sources, do not forget about salmon! They are a great source of healthy, monounsaturated fats, which contribute to reducing cholesterol (Kris-Etherton et al., 1999), promoting weight loss (Pelkman et al., 2004), and reducing the risk of rheumatoid arthritis (Miggiano and Gagliardi, 2005), and cardiovascular disease (Kris-Etherton et al., 1999; Pelkman et al., 2004). It is also a great source of protein, Vitamin D, Vitamin B12, tryptophan, and selenium.


When cooking salmon, be careful not to overcook it. Salmon can be overcooked very easily, so use methods that keep it moist and tender. Broiling is a very quick and easy cooking method for salmon. Preheat the broiler and place a cast iron pan under the heat for 10 minutes. Then, place your seasoned/marinated salmon (do not remove the skin) on the pan and broil for 7-10 minutes. After cooking, the skin will peel off easily. With this quick method, you can enjoy your salmon without overcooking and damaging nutrients.

Dr. O 
"I don't live to eat...I eat to live!"

REFERENCES

1.  Kris-Etherton, P.M., et al., High-monounsaturated fatty acid diets lower both plasma cholesterol and 
          triacylglycerol concentrations. Am J Clin Nutr, 1999. 70: p. 1009-15.

2.  Miggiano, G.A. and L. Gagliardi, Diet, nutrition, and rheumatoid arthritis. Clin Ter, 2005. 156(3): p. 
          115-23.

3.  Pelkman, C.L., et al., Effects of moderate-fat (from monounsaturated fat) and low-fat weight-loss diets on 
          the serum lipid profile in overweight and obese men and women. Am J Clin Nutr, 2004. 79: p. 204-12.

Tuesday, December 13, 2011

How To Get Your Kids To Eat Healthy Foods


 
          About two weeks ago, I was asked by Cooking with the Troops CEO, Blake Powers, to volunteer at a Marine & Family Holiday Dinner and provide some type of nutritional education for children.  Of course, I jumped at this opportunity.  But in preparation for the event, I initially struggled with deciding on what to present to the kids.  All of the scientific topics I’m used to discussing were definitely out of the window.  After spending a couple of days in thought, I recalled the time I spent with my niece and nephew during Thanksgiving.  While with my family, I tried to share some of my views on eating habits to encourage them to eat healthier foods (i.e. - brainwash them).  What I was reminded of was the fact that my nephew was very willing to eat healthy food, as long as it tasted good.  So, I now had my area of focus: making healthy foods taste good.  But, how could I do that in a way to get kids involved and interested?
          Well, for those that don’t know, I make the best smoothies!  But, only healthy smoothies of course!    So there it was!  I would show the kids a simple way to make healthy foods taste good: smoothies.  It is a simple way to add fruits AND vegetables into their diet, simple enough that most kids can do it on their own.

During my smoothie demonstration.
          So for my smoothie demonstration, I had the following ingredients:  V-8 Fusion (Strawberry Banana flavor), milk, strawberries, bananas, peanut butter, and SPINACH!  Why spinach?  I wanted to show the children that there a ways to make “nasty” vegetables taste good.  With my first demonstration, I added all of these ingredients together, and LOADED the blender with spinach on purpose.  Some children were reluctant to try the smoothies after seen that (LOL!).  But once they tried it, they all liked it!  Not only did they like it, they wanted more!  So, to all of their enjoyment, I kept making more smoothies. 

          Also, to make things more interactive, I gave some of the kids the chance to make their own smoothie.  This strategy reinforced how easy it is to make healthy foods taste good.  Not only were they adding fruits and peanut butter, but they were also adding spinach…by themselves!  My favorite quote from one of the kids was, “I don’t like spinach, but I like it in my smoothie!”  Once I heard that, I knew I had accomplished my goal.  Now, some of these kids will no longer associate “healthy food” with “terrible taste”.  In my opinion, that is the major deterrent that prevents some children from eating healthier foods.  Some parents also came up to me saying, "Now my kids are asking for a blender!".  As I said...mission accomplished!
Me with Cooking With The Troops CEO, Blake Powers, and my smoothie assistant for the day.  He was with me for over an hour making different smoothies!  And they say it's hard to get kids to enjoy eating healthy.  HA!
          So, what’s the take home message from this experience?  This event confirmed that kids are VERY willing to eat healthy foods, as long as they taste good.  However, it is up to parents, caregivers, and educators to provide the healthy foods and discuss with kids why it is important.  And the earlier you start, the easier it is.  Once your children know that healthy foods are better for them, you must help them avoid associating “healthy foods” with “terrible taste”.  Smoothies are a great start, but don’t stop there!  Continuously find recipes for tasty, healthy meals with vegetables to reinforce how good vegetables can taste.  As your children grow to be young men and women, they may be more likely to include vegetables in their meals and most importantly, have better health.

Dr. O 
"I don't live to eat...I eat to live!"

For more information on Cooking With The Troops, please visit their website: http://www.cwtt.org

Monday, December 5, 2011

Cancer and Your Diet: Introduction

**I decided to change the title due to some confusion that it caused.  This blog is not saying that a proper diet can COMPLETELY prevent cancer.  It is simply saying that it MAY HELP REDUCE RISK OF CANCER.***

          This week, ESPN has dedicated much of their coverage toward the V Foundation for Cancer Research, which was cofounded by ESPN and former NC State Men’s Basketball coach, Jim Valvano (a.k.a. - Jimmy V), who was diagnosed with cancer at age 46 and lost his battle with cancer in 1993.  In light of their coverage, I thought that this would be a great time to start a series of blogs regarding the disease that has affected so many people and their families around the world.  Whether it is breast cancer, prostate cancer, colon cancer, cervical cancer, or other types of cancer, the damage that this disease can cause is devastating.  However, while so much emphasis is placed on finding a cure for cancer, much more emphasis should be placed on cancer prevention

          So, why is there not enough emphasis placed on cancer prevention?  Well, in my opinion, many people believe that cancer is just a random occurrence.  Some may think they are just unlucky.  Or maybe that child in their family that developed cancer was just unlucky, and everyone else in the family is fine.  Well, there are factors other than your genetics that play a role in cancer development.  Two co-factors that play a role in cancer prevention (or development) are your epigenetic code and your diet.    

          Epigenetics is the study of alterations in gene activity that do not involve changes to one’s genetic code, but still get passed down to at least one generation. These changes in gene activity are orchestrated by your epigenome, which can significantly alter certain genes without changing the actual DNA sequence.  In other words, your epigenome can tell a gene to “speak” normally, loudly, softly, or not at all.  Furthermore, changes in your epigenome of have been shown to contribute to cancer formation. 

          So, what causes these epigenetic changes?  While there are several environmental factors that can be involved, one of the biggest factors that can influence your epigenetics is YOUR DIET!  A proper diet can provide necessary nutrients to protect your DNA from harmful epigenetic changes.  On the other hand, an unhealthy diet may leave you vulnerable to changes in gene expression that can potential lead to tumor formation.  Even worse, epigenetic changes (good or bad) can be passed down to you from your parents, grandparents, great grandparents, etc.  So, if you come from a family that is not the most health-conscious, you are at FAR greater risk!  And compared to someone from a health-conscious family, it will take FAR LESS unhealthy eating in a person from an unhealthy family to initiate diseases such as cancer. 

          But some might say, “My family and I have been living healthy, so we should be OK, right?”  Well, I’d answer that question with a question.  

Are you really living healthy?

          For example, many people eat grilled food everyday without vegetables and consider themselves “healthy”.  But, some of the same people don’t know that grilling meat can produce carcinogens that can develop into cancer over time.  Many people drink diet soda and consider themselves “healthy”.  But if you read my blog about diet soda, you’d know that it’s not healthy.

          So, my goal with this blog series (and blog overall) is to provide evidence regarding 1) what REALLY is healthy, 2) what common factors can initiate epigenetic changes, and 3) dietary strategies that may help you protect yourself and your loved ones from diseases such as cancer.  If you’d like to get started, read my blog about the anti-carcinogenic properties of broccoli.

Dr. O 
"I don't live to eat...I eat to live!"

Thursday, December 1, 2011

The Power of Music During Exercise


          Music is such a powerful source of motivation during exercise.  Although we get used to listening to our favorite songs during a workout, we can never perform at the same intensity on the days we forget our MP3 player at home!  But why is that?  Why does music help us lift more weight?  Why does the uptempo music in an aerobics or spinning class help us push ourselves to the extreme limits?  And why do we sometimes feel so weak without it?  Well, significant research has investigated the psychophysical and ergogenic effects of music during exercise, and the results are pretty interesting.

          Psychophysics is the study of how physical stimuli can affect sensations or perceptions.  A variety of psychophysical studies have demonstrated how synchronous music during exercise acts as an ergogenic aid, or an external force that positively influences human performance.  Music is considered synchronous when it elicits repetitive body movements in time with the beat or tempo of a song.  The use of synchronous music can be utilized to enhance performance during exercises such as bench stepping (Hayakawa et al., 2000), cycling (Anshel & Marisi, 1978), callisthenics (Uppal & Datta, 1990), 400-m running (Simpson & Karageorghis, 2006), or circuit training (Michel & Wanner, 1973).  Even though Anshel & Marisi (1978) arbitrarily chose music from the “popular rock category” and did not consider the musical preferences of all subjects, synchronous music still induced longer endurance than asynchronous music or no music at all.

          While psychophysical studies can suggest an effect of music as stimuli during exercise, it can not identify a cause.  However, several hypotheses have been made.  Bonny (1987) suggests that the rhythm of music relates to the various rhythms of the human body, such as walking, breathing, or the beat of the heart.  Studies also suggest that synchronous music increases neuromuscular efficiency, which reduces the metabolic cost of exercise (Smoll & Schultz, 1978; Szmedra & Bacharach, 1998). 

          So, if you don’t listen to music while you exercise, give it a try!  Purchase a small MP3 player (nothing fancy is necessary) and upload your favorite songs.  If you synchronize your movements during exercise with your music, you can reduce the your perceived exertion, resulting in greater endurance and more intense workouts!

Dr. O 
"I don't live to eat...I eat to live!"

References

1.   Anshel, M.H. and D.Q. Marisi, Effects of music and rhythm on physical performance. Research Quarterly, 1978. 49: p. 109-113.

2.   Bonny, H.L., Music the language of immediacy. The Arts in Psychtherapy, 1987. 14: p. 255-261.

3.   Hayakawa, Y., et al., Effects of music on mood during bench stepping exercise. Perceptual and Motor Skills, 2000. 90: p. 307-314.

4.   Michel, W. and H.U. Wanner, Effect of music on sports performance. Schweizerische Zeitschrift fur Sportmedizin, 1973. 23: p. 141-159.

5.   Simpson, S.D. and C.I. Karageorghis, The effects of synchronous music on 400-m sprint performance. Sports Sci, 2006. 24: p. 1095-1102.

6.   Smoll, F.L. and R.W. Schultz, Relationships among measures of preferred tempos and motor rhythm. Perceptual and Motor Skills, 1978. 8: p. 883-894.

7.   Szmedra, L. and D.W. Bacharach, Effect of music on perceived exertion, plasma lactate, norepinephrine and cardiovascular hemodynamics during treadmill running. Int J Sports Med, 1998. 19: p. 32-37.

8.   Uppal, A.K. and U. Datta, Cardiorespiratory response of junior high school girls to exercise performed with and without music. Physical Education and Sports Science, 1990. 2: p. 52-56.

Thursday, November 24, 2011

F4: Fats for Fighting Fat - Avocados


Avocados are one of the BEST sources for healthy fat.  About 75% of avocado calories come from fat, most of which are healthy, monounsaturated fats.  Avocados are also high in potassium, fiber, and vitamins B, A, and K.  Research also suggests that a diet rich in avocados can reduce LDL and triglyceride levels and increase HDL levels (Lopez 1996).  Avocados are also sources of the natural sugar, D-mannoheptulose, which has the potential to reduce insulin secretion in hyperglycemic patients (Viktora 1969).  They are also a source of digestive enzymes, such as lipase (for fat digestion) and cellulase (for the digestion of cellulose, found in fibrous vegetables), that can help reduce constipation.  

But be careful!  These enzymes are VERY sensitive to heat, so eat them raw to get these great health benefits.  Eat them as an additional side dish or with your salad.  No matter how you eat them, avocados should be a part of everyone's diet!

Dr. O 
"I don't live to eat...I eat to live!"

REFERENCES

Lopez, L.R., et al., Monounsaturated fatty acid (avocado) rich diet for mild hypercholesterolemia. Arch Med 
         Res, 1996. 27(4): p. 519-23.

Viktora, J.K., et al., Effect of ingested mannoheptulose in animals and man. Metabolism, 1969. 18(2): p. 
         87-102.

Sunday, November 20, 2011

Healthy Foods Don't Have Higher Costs



What do you value more: your health or your money?

Most people would immediately say, “My health of course!”  But is that really true?  Due to some people’s finances, I understand that some may have to sacrifice the health benefits of high quality food and purchase lower quality.  However, in many cases, individuals who can easily afford healthier foods choose to settle for more convenient, unhealthy options.  Here are a couple of simple questions that will describe the problem that exists with many Americans today. 

1. Would you rather pay for an Extra Value Meal from McDonald's or a healthier chicken salad that is double the price?  

Many people would choose the Extra Value Meal and not think twice.  Unfortunately, such an individual may only be considering the monetary cost of this meal.  Do you not consider the “health cost” at all?  Is your long-term health not worth the extra money?  

Here’s another question: 

2.  When choosing a drink with your meal, you have two options: a) a fountain drink (water is not available at the fountain), or b) bottled water that is double the price of the fountain drink.  Which would you choose?

Once again, many people would choose the fountain drink because the bottled water has a higher monetary cost.  Even if you have a diet drink, if you read my blog on diet soda, you’d know that the health cost associated with a diet drink is much higher than water.

So what’s the point of all this?  With every food or drink that we consume, we must not only consider the monetary cost, but also the health cost. It's quite simple:

Total Meal Cost = Monetary Cost + Health Cost

In our first example, although an extra value meal has a much lower monetary cost than a grilled chicken salad, the health cost is significantly higher.  Similarly, a cheap fountain drink also has a lower monetary cost than bottled water, but the health cost is significantly higher.  You don’t pay these health costs up front but you will eventually, through doctor visits, hospital bills, prescriptions, quick fix weight loss strategies (fat burners, liposuction, gastric bypass surgery, HCG diet etc.), and emotional distress associated with low self-esteem.  Also, if you’re running a company, don’t forget to consider the healthcare insurance costs of each employee for fees from the aforementioned list.

And even for those who eat healthy, the unhealthy eating of others still affects you, so it is still important to encourage others to do the same.  Not only is it the right thing to do, but it will help to reduce the amount of money taken from YOUR INCOME to finance public healthcare, such as Medicare.

So ask yourself, which option truly has the greater cost?

Dr. O 
"I don't live to eat...I eat to live!"

Saturday, November 12, 2011

Negative Effects of Antibiotic Use


Whether you are prescribed with azithromycin, doxycycline, vancomycin, or others, antibiotic treatment is very effective at eliminating harmful bacteria from living organisms.  However, there are drawbacks to its use which can negatively affect your health.  While antibiotics for infection eliminate “bad” bacteria, they also eliminate “good” bacteria, such as Lactobacillus acidophilus, in your digestive tract.  These bacteria, known as probiotic bacteria, are essential in maintaining proper digestive health.  Their elimination can cause diarrhea, malnutrition, improper breakdown of foods, the accumulation of “bad” bacteria. 

This issue is further complicated by the potential for antibiotic resistance.  Bad bacteria can develop a resistance to antibiotics, allowing them to accumulate along the digestive tract due to the absence of probiotic bacteria.  This can lead to further infections and disorders such as antibiotic-associated diarrhea (AAD). 

So, if you antibiotic treatment is prescribed to you, the best strategy is to supplement with probiotics, such as Lactobacillus acidophilus supplements, immediately after antibiotic treatment.  This will allow probiotic bacteria to re-colonize the digestive tract and maintain its health and proper function (McFarland 2006).

Natural food sources have also been identified as having anti-bacterial properties.  In my next blog, I'll tell what these sources are.

Dr. O 
"I don't live to eat...I eat to live!"
-----------------------------------------------------------------------------------------------

References

1.    McFarland, L.V., Meta-Analysis of Probiotics for the Prevention of Antibiotic Associated Diarrhea and the Treatment of Clostridium difficile Disease. Am J Gastro, 2006. 101: p. 812-22.

Monday, October 17, 2011

Diet Drinks: They Are NOT What You Thought They Were

Outline
I.  Introduction
II.  Artificial Sweeteners and Weight Gain
III. Artificial Sweeteners, Appetite, and the Food Reward System
IV. Artificial Sweeteners and Adverse Events?  Still Unclear
V. Dr. O's Final Thoughts
VI. References
 -----------------------------------------------------------------------------------------------
I.  Introduction
And what did you think they were?  Healthy.  You thought they help you lose weight.  You thought these products were made for health conscious people.  And the media/marketing machines have worked to perfection.  Historically, women have been the main consumers of diet sodas.  Now, these drinks are being re-branded as “Such & Such” Zero, packaged in “manly” colors (i.e. – black), and now more than ever, more men are consuming these drinks.  In reality, NO health conscious person should be drinking diet drinks.  The artificial sweetener, aspartame, is the major ingredient found in diet sodas, Equal, and NutraSweet.  It provides the sweet taste without the calories.  Other commonly used artificial sweeteners include saccharin, acesulfame-K, and sucralose (Splenda).  I know a lot of people say that diet drinks make you crave sweet even more.  Well, for the people who don't believe that, I'm here to share scientific studies that might change your mind.  Many studies have shown that aspartame, and artificial sweeteners in general, make it harder for you to lose weight and increase sugar cravings.   
 -----------------------------------------------------------------------------------------------
II. Artificial Sweeteners and Weight Gain
 
     A. Epidemiological Studies

Epidemiological studies suggest that artificial sweetener and diet soda consumption can contribute to weight gain.  In a study by Fowler et al. (2008), 5,158 adults from San Antonio, Texas were measured for their height, weight, BMI, and artificially sweetened beverage (ASB) consumption (baseline).  ASBs included diet drinks, sweetened coffee, and sweetened tea.  Seven to eight years later (follow-up), 3,682 of those residents were re-examined for incidence of being overweight, obesity, and change in BMI. 

Normal weight individuals who reported drinking less than 3 artificially-sweetened beverages per week at baseline and at follow-up were 1.5 times more likely to be overweight or obese at the 7-8 year follow-up than those who did not drink ASBs.  Those reporting 3-21 ASBs per week were 1.75 times more likely to be overweight or obese.  Those reporting 22+ ASBs per week were 2 times more likely to be overweight or obese.  Also, individuals who reported drinking 3+ ASBs per week also had significantly higher BMIs.  This data does not suggest that sweeteners are the main cause of these changes.  However, there is clearly a “positive dose-response relationship” between ASB consumption and weight gain. 

Even more disturbing, this relationship also exists with children.  Forshee et al., (2003) conducted “descriptive and multivariate regression analysis of children aged 6-19 from the US Department of Agriculture’s Continuing Survey of Food Intake by Individuals”.  Results suggest that the consumption of diet carbonated drinks (aspartame) positively correlates with an increase in BMI.

A similar study by Nettleton et al. (2009) also showed that diet soda (aspartame) consumption positively correlates with metabolic syndrome and type 2 diabetes among those who participated in in the Multi-Ethnic Study of Atherosclerosis.

     B.  “So how do artificial sweeteners actually make you fatter and put you at greater risk??”

One answer may lie in the amount of calories that people consume during the day while drinking a “diet” drink.  Simply put, in the mind of some, diet drinks free up calories to be consumed from other sources.  You know, the “I drank all diet drinks today, so I’ll eat some ice cream to reward myself” type of people.  This lack of discipline and the intake of the wrong foods results in caloric intake above one’s weight maintenance level, malnutrition, and fat gain.  Artificial sweeteners themselves don’t make you fatter, but they give a false sense of comfort, which can make you more willing to make the wrong decisions in your diet.  Let’s be clear: DIET DRINKS DON’T DO MAGIC!  Caloric restriction, proper nutrition, and exercise are the only ways to lose weight.  Just drinking diet drinks will not help or speed up the process. 

A study by Knopp et al. (1976) showed that aspartame does not speed up weight loss.  This study assessed the effect of aspartame (2.7g/day for 13 weeks) in combination with a calorie-restricted diet (1000 calories/day) on subject with a mean age of 19.3 years, mean body weight of 164.6 lb, mean height of 65.4 in and 33% in excess of ideal body weight.  There was no significant difference in weight loss between the aspartame group and the placebo group.  Also, changes in glucose, immunoreactive insulin, and immunoreactive glucagon were characteristic of a calorie restriction, suggesting that aspartame played no role in weight loss.

This was also shown by Blackburn et al. (1997), who randomly assigned 163 obese women to a 19-week weight loss program which either allowed or avoided aspartame-sweetened foods and beverages for 16 weeks.  Dieticians guided subjects on nutrition and exercise.  The no-aspartame group was encouraged to use sugar and/or honey as sweeteners.  Subjects were instructed to complete 200 min of aerobic exercise per week; however, no details were provided on caloric intake during this weight loss program.  The authors state that “The same group leader led both groups (aspartame group and sugar/honey group) to ensure uniform treatment”.  I have no idea if that means equal caloric intake or not.  But the main point is that this weight loss program resulted in similar weight loss in both the aspartame and no-aspartame group. 
 -----------------------------------------------------------------------------------------------
III. Artificial Sweeteners, Appetite, and the Food Reward System

I know what some are thinking:  “Well duh! As long as I reduce my calories, eat the right foods, then I can still drink diet drinks to scratch my soda/fruit drink itch and lose weight!”  Not so fast, my friend! 

While you can still lose weight, several issues remain.  Studies suggest that artificial sweeteners increase human appetite.  Black et al. (1992) showed that subjective appetite through the day was significantly higher in patients who consumed 280 ml of carbonated mineral water sweetened with 340 mg aspartame vs. subjects who consumed 280 ml of unsweetened carbonated mineral water.  So while it is possible to lose weight while consuming aspartame, you are making it more difficult for yourself by consuming artificially sweetened drinks.  Interestingly, this study also showed that consuming 280 ml of carbonated mineral water with 340 mg aspartame in capsule form did not increase subjective appetite.  This result suggests that the actual tasting of aspartame induces the increased appetite. 

This begs the question: What response occurs on the tongue that causes increased appetite?  The answer may involve the neurological responses to glucose versus artificial sweetener consumption.

To gain a better understanding of the “increased appetite” response, it is important to have a general understanding of the food reward system, which is a part of your nervous system.  Your taste buds are a part of your food reward system, where taste receptors ascend through the thalamus and into the cerebral cortex.  I won’t go into great detail about the neuroanatomy, but one important note is that dopamine, the “reward” neurotransmitter, is crucial in facilitating the reward response in the brain from taste receptors and signaling satisfaction, or in this case, quenching your sugar craving.

So, with that background, let’s dig into the research.  Studies have shown that artificial sweeteners do not activate the food reward system in the same way as natural sweeteners.  A study by Smeets et al. (2003) used functional MRI to illustrate that consuming aspartame-sweetened beverages does not induce the same response as glucose-sweetened beverages in the hypothalamus, the part of the brain that releases dopamine and regulates hunger.  Glucose-sweetened beverages induced a significant, prolonged decrease in hypothalamic activity, while aspartame-sweetened beverages did not.  So, while you taste something sweet with a diet drink, your food reward system may not actually recognize it since it is artificial.  Therefore, the demand for sweets in your hypothalamus will not decrease (as it would with natural sweets).  What’s the result? 

You asking yourself why you’re still craving sweets after drinking diet drinks all day.  This may cause you to binge more and more on sweets OR fight with your cravings all day and night, making you go crazy.  Sound familiar?

Furthermore, while natural and artificial sweeteners bind to the same sweet taste receptors, they do not bind in the same way (Morini et al., 2005).  This binding difference may also play a role in the altered brain response to artificial sweetener consumption.
 -----------------------------------------------------------------------------------------------
IV. Artificial Sweeteners and Adverse Events?  Still Unclear

Many studies have investigated the development of adverse reactions associated with artificial sweeteners.  Unfortunately, these studies present conflicting results.  Some individuals have reported headaches, dizziness, or gastrointestinal discomfort from artificial sweetener consumption, while others have not.  At this point, a definitive answer is not available.  However, I’m sure that further research will provide answers.  Animal studies are useful in providing insight into how artificial sweeteners might affect the body.  But no conclusions about humans can be made from animal studies.  Therefore, there is a limit on how much data can be acquired from human subjects. 
 -----------------------------------------------------------------------------------------------
V. Dr. O's Final Thoughts

What we do know is that artificially sweeteners do not stimulate the same brain response as natural sweeteners.  Studies suggest that artificial sweeteners may not stimulate the food reward system effectively, resulting in the maintenance of sugar cravings.  Long-term adverse events from artificially sweetener consumption have been reported, but studies have presented conflicting results.  However, in regards to weight loss, it is clear that diet sodas make it harder to lose weight.  Here's the hypothesized chain of events:


1.  Artificially sweetener binds to taste receptors in an unnatural way.
2.  Binding induces stimuli to the brain that is different from natural sweets.
3.  The reward center in the brain (hypothalamus) does not receive the normal "sweets have been eaten, I don't need them anymore" signal.
4.  You still crave sweets.

Then the following could happen:

5.  You drink more "Diet Such & Such Zero"
6.  You still crave sweets.
7.  You drink more "Diet Such & Such Zero"
8.  You still crave sweets.
:
:
:
71.  You drink more "Diet Such & Such Zero" 
72.  You still crave sweets.
73.  You give in and go on a sweets binge.

Yes, extreme...but you get the point.  Stop drinking diet drinks.

Dr. O 
"I don't live to eat...I eat to live!"
  -----------------------------------------------------------------------------------------------
VI. References


1.    Black, R.M., L.A. Leiter, and G.H. Anderson, Consuming aspartame with and without taste: differential effects on appetite and food intake of young adult males. Physiol Behav, 1993. 53(3): p. 459-66.


2.    Blackburn, G.L., et al., The effect of aspartame as part of a multdisciplinary weight-control program on short- and long-term control of body weight. Am J Clin Nutr, 1997. 65: p. 409-418.


3.    Forshee, R.A. and M.L. Storey, Total beverage consumption and beverage choices among children and adolescents. Int J Food Sci Nutr, 2003. 54(4): p. 297-307.


4.    Fowler, S.P., et al., Fueling the Obesity Epidemic?  Artificially Sweetened Beverage Use and Long-term Weight Gain. Obesity, 2008. 16: p. 1894-1900.


5.    Knopp, R.H., K. Brandt, and R.A. Arky, Effects of aspartame in young persons during weight reduction. J Toxicol Environ Health, 1976. 2(2): p. 417-428.


6.    Morini, G., A. Bassoli, and P.A. Temussi, From Small Sweeteners to Sweet Proteins: Anatomy of the Binding Sites of the Human T1R2_T1R3 Receptor. J Med Chem, 2005. 48: p. 5520-5529.


7.    Nettleton, J.A., et al., Diet Soda Intake and Risk of Incident Metabolic Syndrome and Type 2 Diabetes in the Multi-Ethnic Study of Atherosclerosis (MESA). Diabetes Care, 2009. 32: p. 688-694.


8.    Smeets, P.A.M., et al., Functional magnetic resonance imaging of human hypothalamic responses to sweet taste and calories. Am J Clin Nutr, 2005. 82: p. 1011-1016.


9.    Yang, Q., Gain weight by "going diet?"  Artificial sweeteners and the neurobiology of sugar cravings. Yale J Bio Med, 2010. 83: p. 101-108.