Leptin and Appetite: Feeling Full or Fleeced?

By Katie Clark, MPH, RD

Up until a few years ago, scientists believed that fat tissue (also called adipose tissue) was a metabolically inactive organ that just padded your organs, insulated your body, and when accumulated in excess, expanded your waist-line. In 1994, researchers at Rockefeller University identified leptin as the hormone actually produced by fat tissue that signified satiety–or the feeling of fullness–in a group of obese mice they were studying.

Since then, the idea of leptin as a weight-loss “miracle” has been touted by supplement makers and everyone else with an interest in the lucrative weight-loss industry. While plenty of scholarly papers and animal studies regularly analyze the role of leptin, as a consumer, exactly how effective is leptin or leptin-containing products for weight-management? And how can you really promote appetite control for weight-loss?

Leptin’s Broken Promises

Essentially, leptin tells your fat stores that you have enough fat stored up in your body. When adequate fat mass exists, your fat cells secrete leptin. Theoretically, your accumulation of additional fat will stop with the introduction of leptin into the bloodstream. Nutrition researchers, and later the dietary supplement industry, used this relationship to surmise that if you can figure out how to increase leptin production, you can halt fat storage and promote weight loss in someone who would otherwise continue to get fatter.

While genetically mutant obese mice that had no leptin production lost weight when injected with leptin, the same has not held true when applied to human subjects. Contrary to public opinion, scientific literature has never demonstrated that ingested or injected leptin has induced weight loss in otherwise healthy overweight humans. Because the mechanism by which leptin works is not entirely understood and because there are basically no humans who entirely lack leptin production, the reason why overweight humans who were given leptin but did not lose weight is also somewhat of a mystery.

Losing Weight the Approved-Drug Way

To date, there are no FDA-approved weight-loss drugs that utilize leptin as the weight-loss-inducing ingredient. At any given moment there is probably a slew of drug companies researching the potential for leptin in a weight-loss drug, but it is not currently a viable option for American consumers.

Supplement manufacturers are still on the leptin bandwagon, however, and you can find hordes of weight-loss dietary supplements claiming to have leptin as an active ingredient. Because the dietary supplement industry is highly unregulated, consumers should take caution and know that the likelihood of leptin causing weight loss is the only slim thing about these claims.

The two drugs that are approved for long-term weight-loss and maintenance by the FDA are the following:

  • Sibutramine (Meridia™) – a serotonin-norepinephrine reuptake inhibitor that works on receptors in the hypothalamus (the brain’s “satiety center”) to reduce appetite.
  • Orlistat (Xenical™) – stops the action of gastrointestinal lipase (a fat-breakdown enzyme) and reduces fat absorption, resulting in increased fat loss in the feces. The popular over-the-counter weight loss drug Alli™ is a lower-dose version of Xenical.

The Science of Satiety

If (and until) leptin re-emerges as a practical weight-loss application, you can alter your diet to more naturally increase satiety. Satiety is the feeling of being full, and protein and fiber are the two nutrients that can help you accomplish this—which in turn, helps prevent overeating elsewhere in your diet.

Exactly how protein helps to promote satiety is not entirely known. It may serve to increase circulating levels of leptin, or increase in the level of cholecystokinin release that slows the emptying of food from the stomach during digestion.

Fiber works to keep you fuller because it also slows down the rate of digestion. You might notice that if you eat a piece of low-fiber white toast or white bagel, you get hungrier again more quickly than if you eat the same amount of calories of a 100% whole wheat bagel or piece of high-fiber bread. High fiber foods take longer to digest, meaning that there is more time until the next time when you get hungry again.

Some food manufacturers are starting to realize the importance of promoting satiety. One such company is LightFull Foods™, a San Francisco-based outlet that produces LightFull smoothies. These 11-oz. smoothies are low in calories (90 calories/serving) and have a good amount of fiber and protein (5-6 grams of both, depending on the flavor). While some nutrition professionals would argue that calories from drinks do not keep you as full as calories from foods, as far as satiety is concerned, a beverage that contains protein and fiber instead of high fructose corn syrup and high levels of refined carbohydrate, is definitely a step in the right nutritional direction.

The Protein-Fiber Combo

In order to promote optimal satiety throughout the day and in order to prevent overeating, keep these numbers in mind when it come to fiber and protein: Women need 25 grams of fiber per day and men need 38 grams. Most adults need somewhere between 75-125 grams of protein per day, depending upon your activity and calorie level. Scheduling an appointment with a registered dietitian is a good way to help determine what your optimal, personal calorie and protein needs are.

So while leptin as a supplement will not promote any substantial weight loss, and leptin as a prescription drug is probably years away, it does not hurt to focus on satiety in other food-based forms. Bump up your fiber and protein intake—without increasing calories—and you’ll have a safe, natural appetite control mechanism that really works to curb your food intake.


  • A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations. Weigle, et al. Am J Clin Nutr. 2005 Jul;82(1):41-8.
  • Appetite Regulatory Hormone Responses to Various Dietary Proteins Differ by Body Mass Index Status Despite Similar Reductions in ad Libitum Energy Intake. Bowen, et al. J Clin Endocrinol Metab. 2006 Aug;91(8):2913-9.

The Coke Zero Craze

Monday, July 14, 2008 - 4:16pm

By Donna Feldman, MS, RD

With soft drink sales declining, as consumers switch to bottled water, teas, and energy drinks, what does the world’s No. 1 beverage company do? Create another soft drink--Coke Zero. Sales of Coke Zero, introduced in 2005, have surged recently thanks to some clever marketing that plays up a cool, edgy, youthful image. But consumers don’t drink the image for long, so there must be more to Coke Zero than clever marketing.

What’s the Difference?

The one clear difference between Coke Zero and Diet Coke is the taste. Diet Coke, sweetened only with aspartame, is less sweet-tasting than regular Coke Classic, and has it’s own distinctive flavor. Coke Zero was sweetened and flavored to mimic Classic as closely as possible, using two artificial sweeteners: aspartame and acesulfane potassium. For consumers who like Coke Classic, but who also want to cut calories, Coke Zero is the obvious choice. They don’t have to settle for a taste they don’t like in order to control calories. As Scott Williamson, Coca Cola spokesperson says “Taste is the cause of it’s success”. As in most things dietary, consumers aren’t willing to sacrifice taste to cut calories. They want both. In Coke Zero, they get the Classic taste with about 2 calories per 12-oz can, rather than 150.  For a person who drinks just one can a day, this is a savings of over 1000 calories per week.

Men vs. Women

Many web commentaries about Coke Zero presume the drink is targeted to men, who supposedly don’t respond favorably to the word “Diet” on a product. So are men the primary Coke Zero drinkers? Not according to Williamson, who says men and women are buying it in pretty equal numbers. The truly significant purchasing difference is in age groups. Thanks to the recent web-based marketing efforts, Coke Zero is appealing to the tech-savvy younger crowd of calorie-conscious consumers. The funniest example is a video that features Coca Cola executives talking to unsuspecting lawyers about suing their own employees for “taste infringement”. The video, available on the Coke website, succeeds in playing up the taste similarities between Coke Zero and Coke Classic.

What about the Sweeteners?

Both aspartame and acesulfane K are low-calorie, artificial sweeteners.  Consumers who dislike these types of products probably won’t like Coke Zero any better than Diet Coke or any other low calorie drink. But for calorie-conscious people who still want a flavored, carbonated beverage, Coke Zero represents another option that won’t add to the hips or waistline. For Coke Classic fans, cutting calories is now easier.


Excess calories don’t have a place in our weight-conscious world, but consumers won’t settle for low-calorie products that don’t deliver taste. Coke Zero is an example of a product designed to address both those demands. Our one-can-a-day person saves 1000 calories a week, and 52,000 calories in a year, by switching to Coke Zero. This could add up to a 15-pound weight-loss over that year, thanks to one simple change. Now if only someone would invent Burger Zero…


1.    http://www.bloggingstocks.com/2007/11/23/hottest-products-of-2007-coca-cola-shakes-up-coke-zero/
2.    http://en.wikipedia.org/wiki/Coca-Cola_Zero
3.    http://www.coca-cola.com/
4.    Scott Williamson and Joan Kennear RD, personal communication, (December 2007).

*This article is intended for general information purposes only, is not individual-specific, nor is it intended to replace the advice of your healthcare team.

Tips for Getting Your Kids off the Couch this Summer

Monday, July 14, 2008 - 4:09pm

By Michele Silence, MA

By now everyone knows how important it is to get kids off the couch and moving. However, if the kids are used to surfing the Internet, playing video games that don’t require much movement (like the Wii), or watching hours upon hours of TV, it may not be that easy. In order to give them some much needed exercise, you’ll have to motivate them to be active. Here are some suggestions:

Find What They Like

Take a week to explore different activities. Take a bike ride together; go swimming; hike up a woodsy trail; or jump on a boogie board and ride some waves. Try out anything that could easily turn into a weekly activity with the kids. Find out which one(s) your kids express the most interest in and seem to be the most excited about. Do these activities at least once a week with them. It is important that you participate in these activities with your kids. Not only do you bond with your kids, but your excitement for these activities is contagious and will get your kids more pumped.

Limit TV and Computer Time

That, or make it conditional by only allowing it after an hour of exercise a day. This may seem like an uphill battle as kids want to chat with their friends on IM, use Club Penguin, or write on their friends’ MySpace pages. Expect gripes, whining, and (let’s be honest here) tantrums. However, when they go outside to ride bikes with friends or play a basketball game, they’ll quickly see how much fun it is.

Get Your Kid a Gym Membership

This time of year gyms are giving away great deals. If your kids are 16 or older, get them a membership or add them to your own. Encourage their friends’ parents to get their children a membership too. When a few kids get together and go to the gym, it becomes more than just exercise—it’s an opportunity for your kids to socialize while getting a workout. Now gyms, more than ever before, have added fun free classes such as hip-hop aerobics, group cycling, and even air band and krumping classes.

Take part in public Walks/Runs

Just about every weekend you can find a 5 or 10K walk or run to benefit a worthy cause. These events are great motivators for kids. They will see other kids exercising and doing well, and there’s and undeniable sense of excitement in the air. These public walks and runs also foster a sense of competitiveness along with an overall feeling of accomplishment. Many times, the sponsors of these walks/runs hand a medal, t-shirt, or certificate at the finish line, which your child will undoubtedly treasure.

Whatever you choose to do, the important thing is to do something. Help your child start enjoying exercise—just keep focusing on the fun aspect of exercise. Kids today need to move more and eat less. When you help them do either, you are immediately enabling them to improve their health. More than that, you are setting a pattern that they will follow later into their adulthoods and someday pass on to their own kids.

*This article is intended for general information purposes only, is not individual-specific, nor is it intended to replace the advice of your healthcare team.

Your Money or Your Weight Loss

Monday, July 7, 2008 - 4:58pm

By Krista Scott-Dixon, PhD

Many years ago, my mother was desperate for me to pull up my socks and get better grades in school. One night, prompted by a couple of glasses of wine and my mediocre midterm results, she offered me $500 if I got all As in my final year of high school. Ever the business woman, I prompted her to offer $1000 for all A+. Spurred on by financial incentive, I managed very high As, and bargained her out of $750.

For most of us, money is a pretty good motivator. While not all of us are Gordon Gekkos from Wall Street, chanting “Greed is good” as we swindle others out of their dough, we are probably more likely to do something if there’s a pot of money at the end of it (or if by not doing it, we know we’re going to lose some cash).

A study published in September 2007 showed that people could be motivated by money to lose weight. Researchers compared three groups: Group 1 was offered no money; Group 2 was offered a modest amount of money, and Group 3 was offered the most money. Not surprisingly, the people offered the most money lost the most weight. This confirms the results of other studies that show people are more likely to do things like quit smoking if offered financial incentives.

But just how effective is a cash reward? The results of the weight loss study in September were pretty modest, and the biggest effect was in the short term. Three months into the study, Group 1 participants with no financial incentive lost 2 pounds, those in the so-so payback Group 2 lost approximately 3 pounds, and those in the best paid Group 3 lost 4.7 pounds. But after 6 months, when the financial gains were equalized, weight losses were similar across groups. In other words, not much of a difference in the long haul.

Indeed, some might consider saving their cash. A systematic review of the research on cash motivation for weight loss found that in all the studies examined, there was no significant effect of financial incentives on weight loss or maintenance at 12 months and 18 months. Nor was there much of an effect for group versus individual rewards, behaviour based rewards, or rewards handed out by various types of people (e.g. psychologists, employers). In other words, great idea for 3 months, but for long term weight loss and healthy weight maintenance, the wallet only goes so far.

Another recent study in the Journal of the American Dietetics Association suggested that money might only motivate certain things. In this study, researchers tried to combat the problem of people’s poor recall in accurately measuring eating habits, a problem that constantly plagues nutrition studies. (People are not very good at precise recollection of their food intake, just like they’re not very good at eyeballing straight lines when cutting.) In the study, participants were paid to accurately recall their diets -- in other words, to remember precisely what and how much they were eating. The researchers checked the participants’ saliva to see whether they were telling the truth. The smoking studies also found that although there was an effect of money among the people who quit smoking, only a small group actually did quit. In the case of the food reporters and non-quitters, cash made no difference at all!

So what works? Well, money does seem to work for a brief time. But if you’re looking for tricks to stay at a healthy weight for life, you might want to have more than a fistful of dollars.

Finkelstein EA, Linnan LA, Tate DF, Birken BE. A pilot study testing the effect of different levels of financial incentives on weight loss among overweight employees. Journal of Occupational and Environmental Medicine 49 no. 9 (Sept 2007): 981-989.

 Hendrickson S, Mattes R. Financial incentive for diet recall accuracy does not affect reported energy intake or number of underreporters in a sample of overweight females. Journal of the American Dietetics Association 107 no. 1 (January 2007): 118-121.
Paul-Ebhohimhen V, Avenell A. Systematic review of the use of financial incentives in treatments for obesity and overweight. Obesity Reviews (October 23 2007).   

Volpp KG, Gurmankin Levy A, Asch DA, Berlin JA, Murphy JJ, Gomez A, Sox H, Zhu J, Lerman C. A randomized controlled trial of financial incentives for smoking cessation. Cancer Epidemiology Biomarkers Prevention 15 no.1 (January 2006): 12-18.

Resveratrol (aka Red Wine Pills) - Too Soon To Tell

Monday, July 7, 2008 - 4:51pm

By: Stephanie Clarke, MS, RD and Willow Jarosh, MS, RD

The idea of a pill that can prevent Alzheimer’s, prevent and treat cancer, slow aging, decrease inflammation, reduce the risk of stroke, and even reduce the negative effects of a high fat diet is incredibly exciting.  These are some of the claims that manufacturers of red wine pills and resveratrol pills are making.  Over the past year, resveratrol pills have made a surge into many stores and all over the internet, following several studies that indicated that mice fed resveratrol lived longer, healthier lives.  These pills may seem too good to be true – and for good reason, little is known about the effects of resveratrol on humans.  Read on to get the facts on resveratrol and resveratrol pills.

What is resveratrol?
Resveratrol, while often associated with the health benefits of red wine because of its presence in the skin of red grapes, is found in a variety of plants including raspberries, peanuts, white pine, and cranberries.  It’s actually produced by these plants as a defense against bacteria or fungal infection.   The amount of resveratrol in food varies greatly.  In fact, Spanish red wines can have more than twice the resveratrol of Pinot Noir because of the difference in grapes used.

What the studies say
Several major studies conducted in the past couple years have created quite a buzz about resveratrol.  One study found that middle aged subjects fed a high fat diet were less likely to die early (or develop diabetes) if they took large doses of resveratrol.  Another study found that subjects eating a high fat diet along with large resveratrol doses had lower insulin levels (associated with lower risk of heart disease and diabetes), could run twice as far, and weighed nearly the same as subjects on a regular diet who did not receive resveratrol.   The big catch is, the “subjects” in all the resveratrol studies so far have been mice.  There is no data available as to how taking resveratrol affects humans.

Resveratrol supplement recommendations
The potential health benefits of resveratrol are exciting – and could hold promise in the future.  However since there aren’t studies in humans, it’s impossible to say how much resveratrol is needed to create health benefits… or even IF resveratrol supplements will have health benefits in humans at all.  Another thing to consider is that while we don’t have studies to show the benefits of resveratrol in humans, we also don’t know if there are any dangers to taking high doses of resveratrol in the short or long terms.   For instance, it’s recommended that women with a history of estrogen-sensitive cancers not take resveratrol supplements because they could have an estrogen-like affect on the body. 

Wine vs. resveratrol pills
Originally, scientists began looking at resveratrol’s potential health benefits because of its existence in red wine.  Red wine had been linked to The French Paradox (French people have lower rates of heart disease even though they eat relatively high amounts of saturated fat and smoke more than Americans) that pointed out that moderate consumption of alcoholic beverages may be associated with a decreased rate of heart disease.  But, it’s still unclear exactly what about moderate alcohol consumption, or specifically wine consumption, provides the health benefits.  And if you look at the amount of resveratrol the mice in the studies were given, it translates to a 130 pound person drinking about 650 bottles of red wine daily!

The bottom line
The potential of resveratrol supplements is exciting – but it’s too early to tell if they’re safe or not and in what doses.  Until there are more human studies and concrete recommendations, it’s best to steer clear of resveratrol supplements.  If you already drink red wine, do so moderately (2, 5-ounce glasses a day for men, 1 glass for women) and if you don’t, there’s currently no indication that taking up drinking will bring health benefits.  And, of course, protect your heart with a healthy diet and daily physical activity.


UltraSlim XS 300x250

UltraSlim XS 300x250

The Final Frontier......uh.....Plateau

Submitted by Carolyn on Tue, 05/06/2008 - 9:30am.

Good Tuesday Morning:

I've been stuck (as you all know) at a weight plateau for sometime now. So I focused on reading labels and going back to what worked before - "cleaning and dancing". I had gotten away from that enjoyable pasttime due to outside commitments. I have greatly reduced the number of fat grams that I consume daily as I have learned that not all calories are equal. Those dreaded fat calories go right to my....well, let's just call it the old fat farm. Lots of protein, fiber and good carbs. I've now expanded my music library to include not only the Eagles, but Matchbox 20 and Hootie and the Blowfish. My neighbors are loving it I'm sure.

The BIG 58!!!!

Submitted by Carolyn on Tue, 04/29/2008 - 7:47am.

OK.......so tomorrow is a big day for more than one reason. It is the "cut off" date for chocolates and I'm SAFE until Halloweeen. From May through the end of October it is way too hot for chocolate in Florida and there are no summer holidays that celebrate dark chocolate. It's now fresh fruit and refreshing sugar free beverages for me!!!!

It's also my 58th birthday. It's time to take a look back at the last year. I'm still trying to move forward and let go of the bad habits that kept me from living and enjoying life.

After my husband's death, I promised myself that I would live everyday as if it was my last. This meant being GOOD to myself, taking care of my health, losing weight (PERMANENTLY) and maybe, on a really good day, help someone do the same. The last year has presented many opportunities to get the word out, including the Today Show appearance and my Diet Channel blog. I also realized that my weight loss story is my new "purpose". I have been given this opportunity to help others and I have a new found passion.

Why I Love Mexico

Submitted by Carolyn on Wed, 04/02/2008 - 7:28am.

If you've ever been to Mexico, you know that the weather is perfect, the people are warm and wonderful, the beaches are fabulous and the food is, for the most part, fresh out of the sea and very unique. I've had the opportunity over the past two years to visit various locations in Mexico with my personal favorites being San Jose del Cabo and Todos Santos. San Jose del Cabo is a beautiful city on the Sea of Cortez with a very quaint downtown area that includes art galleries, restaurants, churches and fishing. I have learned to enjoy fishing and can add "having caught a 142 pound blue marlin" to my resume.

Spring Into Action

Submitted by Carolyn on Fri, 03/28/2008 - 8:27am.

OK - NO MORE EXCUSES. The chocolate holidays are behind us, the spring flowers are in bloom (tulips are my favorite) and the weather dictates that hiding under sweats and long sleeves will only cause heat rash!!!! Let's take a long, hard look at our short term AND realistic goals. I have always held to the belief that I have TEN POUNDS to lose. Yes, it's true, I have lost ten pounds ten times but I never looked at the overwhelming prospect of losing 100 pounds. Let's look at a ten pound weight loss with a REALISTIC goal of May 15th. This is a little more than a pound a week. To break that down even further, it's about 4000 calories LESS per week.