A study appearing in the the January 4, 2012 issue of JAMA indicates that when people increase the amount of food they eat, where the calories come from may significantly impact whether or not people gain fat when they gain weight.

Following 25 participants on tightly controlled diets, researchers at Pennington Biomedical Research Center in Louisiana found that when calories from protein were increased, while participants gained weight, they mostly gained lean body mass (muscle) and they ncreased thier resting energy expenditure. Those on a lower protein diet, gained body fat and lost muscle.

While controlling calories is obviously an important part of weight management, studies such as this lend insight to how the source of calories impacts critical factors like resting energy use and body composition - both of which have bearing on overall health.

Reference: JAMA. 2012;307[1]:47-55.

Health Benefits of Harder, Shorter Exercise

Exercise has long been show to benefit those with Type-2 Diabetes.  However, the American Diabetes Association current recommends 150 minutes per week of moderate to intense exercise. At just over 20 minutes per day, every day of the year, this recommendation is prohibitive for many.

A study published in the December 2011 issue of the Journal of Applied Physiology has supplied some new data suggesting that there may be other alternatives. Researchers at McMaster University assessed the benefits of of using 30 minutes per week of high-intensity exercise.  They found significant benefits and improvements in key areas of diabetic health.

While the study was very small, and is really just a proof of concept, it is an indication that those with diabetes may be able to get substantial benefits from exercise without lengthy time commitments.

Reference:

Staying physically active is an important part of good health and maintaining your weight.  Some people love the gym, for others a great fitness DVD gets them going, but the outdoors also offers up many options for exercising while enjoying the natural environment.

If you are drawn to exercising outside, but often have thoughts like "it's going to take too long", "what if the trail is too hard for me" or simply "where do I go" then we have found a great app to help you on your way.

The AllTrails app (from AllTrails, inc) give you access to over 40,000 trail guides for everything from walking/hiking to snowshoeing.  By accessing the GPS on your phone it lets you easily browse trails in your area by distance, length (shortest), and most popular.  A simple to use map device will even give you directions from where you are.  Once you choose a trail, you can access the trail map, read reviews by others who have been there, and more.

Because the app also gives you time estimates for completing an activity, you can also plan your outdoor time in a way that you know will work in your schedule.

This app is available both in the iTunes App Store and the Android Marketplace.  It's free - so you don't lose anything by trying it out - but you may just discover something wonderful!

Happy trails!

http://alltrails.com/

This study investigated the relationship of several diet and lifestyle changes such as beverage choices and amount of sleep in nonobese men and women living in the United States. The study combined data from three different, long-term cohort studies—the Nurses' Health Study I and II, and the Health Professionals Follow-up Study—conducted from 1986 to 2006, with more than 280,000 participants. After people with chronic health problems were excluded, data from 120,877 participants were analyzed. Once participants reached age 65, they were excluded from further analysis to avoid confounding due to the loss of lean muscle mass that commonly occurs with age.

Changes in diet and lifestyle factors were measured at four-year intervals. Adjustments were made to take age, baseline body mass and lifestyle factors including physical activity, television watching, alcohol use, sleep duration, and cigarette smoking in account. Dietary factors examined included the amounts of fruits, vegetables, whole and refined grains, potatoes, nuts, dairy products, sweets and desserts, meats, fried foods, alcohol drinks, and trans fat. Several categories were broken down further: boiled and mashed potatoes, french fries, and potato chips; whole-fat and low-fat dairy products; processed and unprocessed meats; sugar-sweetened beverages, diet sodas, and 100% fruit juices; and different types of alcoholic drinks.The relationships between dietary choices and lifestyle factors were analyzed both separately and together.

The results: Small changes in individual behaviors make a big difference in long term weight. The average difference between those with the largest amount of weight gain over the study period and those with the smallest gain or actual weight loss was only 3.1 servings of vegetables per day and 25.3 metabolic equivalents of physical activity per week. Metabolic equivalents (METs) are a practical way to express the intensity of energy expended during various physical activities in a way that is comparable among different levels of physical activities performed by people of different weights. For example, brisk walking at 3 miles per hour, a moderate intensity activity, is roughly equal to 9-10 METs.

While eating more or less of any one food would change the number of calories consumed, the magnitude of weight gain was associated with specific foods and beverages. These show a strong positive association with increased weight gain. Per serving per day, potato chips resulted in a 1.69 pound gain and french fries resulted in 3.35 pounds gained. Refined grains (.39 lb) increased weight gain almost as much as sweets and desserts (.41 lb) per daily serving. Sugared sweetened beverages (1 lb), processed meats (.93 lb) and unprocessed red meats (.95 lb) all showed a similar pattern. The relationship between alcohol consumption and weight gain was not clear and requires more investigation. However, liquid carbohydrates, including alcohol, were associated with increased weight gain.

Less weight gain was robustly associated with increased consumption of other categories of foods. Per serving per day, vegetables resulted in -.22 lb, whole grains in -37 lb, fruits in -.49 lb, and nuts in -.57 lb. Dairy foods overall appear to be neutral. A surprising result was that a daily serving of yogurt was associated with -.82 lb. The authors speculate that the probiotic bacteria in yogurt may alter gut bacteria in such a way that influences weight. Increased consumption of these foods likely means less consumption of those foods associated with increased weight gain.

Physical activities such as sleep and television watching are also associated with long term weight. Weight gain was lowest among those who slept 6-8 hours a night, and was higher for those sleeping less than 6 or more than 8 hours a night. More hours of television watching appears to influence weight gain, and this may due to the opportunity for increased snacking and reduced physical activity. Smoking appears to result in a small initial weight gain, but little weight change afterwards, and the health benefits of smoking cessation far outweigh the associated risks of continuing to smoke as a means of weight management.

Is this study relevant to me? Yes. Anyone interested in maintaining a healthy weight as they age can benefit from the information contained in this study. Eating more nuts, fruits, vegetables, and yogurt appear to reduce weight gain over time, while consuming starches such as potatoes and processed foods high in fat and sugar can increase weight gain. A habitual imbalance of 50-100 calories a day may be enough to result in the gradual weight gain observed in most people.

Limitations of the study: Although this is one of the largest and most comprehensive studies to date on this issue, the study does have some limitations. Portion sizes and lifestyle behaviors were estimated, and could have resulted in some degree of error. The authors note that the true relationship with weight change is likely to be an underestimate. Participants in the study were largely white, educated adults in the United States, which may limit the generalizability of its findings to other populations.

Find this study in PubMed:
Changes in diet and lifestyle and long-term weight gain in women and men.
Mozaffarian D, Hao T, Rimm EB, Willett WC, Hu FB.
N Engl J Med. 2011 Jun 23;364(25):2392-404.

The study question: To what extent is the bone loss that teenagers experience following Roux-en-Y gastric bypass surgery related to weight loss?

This study used a retrospective case review of the charts of 61 adolescent patients who all received the same gastric bypass surgery. Whole-body bone mineral content and density were measured using dual-energy radiograph absorptiometry (DEXA). Where possible, scores for these measures were taken prior to surgery and every three to six months following surgery, for a two year period. Scores for the measures were standardized to make them comparable. Data analysis was adjusted to take age, gender and height into account. All patients were told to take a multivitamin with 1000 mg of calcium and 800 IU of Vitamin D daily following their surgery.  

The results: Patients’ weight, whole-body bone mineral content and bone mineral density decreased significantly over time following surgery, with boys losing more weight than girls. Weight loss was greatest during the first year after surgery, and then stabilized. Whole-body bone mineral content  decreased by 7.4% over two years following surgery. Bone density scores at two years, however, were within the expected values for patients’ age and gender. Weight loss was significantly correlated with the bone loss, but accounted for only 14% of the decrease in bone mineral content in the first year after surgery.

The study raises a number of questions. While there are potential mechanisms to explain just how bone loss could occur after bariatric surgery, these metabolic and hormonal mechanisms need to be investigated in more detail. No one has studied the long-term consequences of weight loss surgery on bone health, so we don’t know whether adolescents who have weight loss surgery could have an increased risk of bone fractures as they age, or not.   

Is this study relevant to me? Yes, if you are a teenager or parent of a teenager who has had or is considering weight loss surgery. While the results regarding bone density scores are somewhat reassuring, teenagers may be at a higher risk for nutritional deficiencies because they may be less compliant about dietary recommendations and taking supplements.

Limitations of the study: The study only included the charts of 61 patients out of the 102 that were eligible. Some patients were excluded because they exceeded the weight limit of the machine used to measure bone density, so those with extreme morbid obesity were not included. This may bias the study results. Not all of the study measures were taken at the same time, which can introduce error. Weight loss can also thicken tissue around bone, resulting in overestimates of bone density, and consequently underestimating the true amount of bone loss. There is also no way to know from studying the patients’ charts retrospectively whether they took the daily multivitamin as instructed.

Find this study in PubMed:

Kaulfers AM, Bean JA, Inge TH, Dolan LM, Kalkwarf HJ. Bone loss in adolescents after bariatric surgery. Pediatrics. 2011 Apr;127(4):e956-61. Epub 2011 Mar 28.

DOI: 10.1542/peds.2010-0785

The study question: Is going to sleep later in the evening associated with other factors that promote weight gain, in and of itself?

This article examined the association between the timing of sleep, that is, what time people go to bed, and whether timing alone was linked to behaviors such as eating more fast food and fewer fruits and vegetables, a higher caloric intake, and having a higher BMI (body mass index), independent of how many hours people slept.

The study sample of 27 men and 25 women was drawn from the Chicago area using flyers and online advertisements. These participants were asked to wear a wrist actigraph, a small device worn on the wrist that records movement during sleep, for 7 days. Data collected from the actigraph was used to determine sleep and wake times, and the total duration of sleep. Participants used food logs to record every food or drink they consumed daily, along with the time, location, description, and quantity of each meal or snack. Fast food was defined as anything that can be purchased from a drive-through. The calorie content of all food and drink consumed was calculated using publically available nutrition information found at www.sparkpeople.com, in conjunction with restaurant and manufacturer websites.

The results: Participants were classified as having normal or late sleep times, and these two groups were compared to each other. Those with normal sleep times had the midpoint of their sleep earlier than 5:30am and those with late sleep time had the midpoint after 5:30 am.

Compared to the normal sleep timers, late sleep timers reported fewer calories consumed at breakfast and more calories at dinner, more calories consumed after 8pm, more fast food meals consumed, more sodas, and fewer fruits and vegetables. Late sleep timers also had shorter sleep duration (5 ½ hours versus 6 ½ hours) and a higher BMI (an average of 26.0, SD = 6.9), compared to normal sleep timers (an average of 23.7, SD = 3.2). Over the 7 days of the study, later sleep timers consumed an average of 248 calories a day more than the normal sleep timers. While this difference was not statistically significant, most of these calories were consumed at dinner and after 8pm, a behavior that was associated with having a higher BMI.

Is this study relevant to me? Yes, if you are trying to lose weight. The results of this study are consistent with previous research about  weight loss, the timing of meals, and sleep. Eating after 8pm and going to sleep later in the evening may increase the risk of obesity.

Limitations of the study: The study used a convenience sample and the sample size is relatively small. The study relied on self-reported information by the participants about their dietary behavior and weight. The researchers did not measure objective metabolic and hormonal markers, so it does not address biological mechanisms that might help to explain the relationship between sleep timing or sleep duration to appetite and weight regulation. Showing an association between a behavior and an outcome alone, in and of itself, suggests but does not conclusively demonstrate a cause and effect relationship between the two.

Find this study in PubMed:
Baron KG, Reid KJ, Kern AS, Zee PC.
Role of Sleep Timing in Caloric Intake and BMI.
Obesity 2011 Apr 28.

The study question: What do we know about the current state of weight loss surgery?            

This article is a position paper from the American Heart Association (AHA) that presents current thinking from the AHA about when bariatric surgery is appropriate, the different surgical options and complications related to surgery, and the subsequent benefits of bariatric surgery, including improvements in cardiovascular risk factors.

While more research is needed to determine which procedures work best for different groups of patients, bariatric surgery is the only effective long-term treatment option for those who are severely obese. There are two main types of surgical procedures. Restrictive operations, which reduce the size of the stomach, include the adjustable gastric band and the sleeve gastrectomy, which removes part of the stomach. Combination operations, such as the Roux-en-Y gastric bypass procedure, combine reducing the size of the stomach with reduced absorption of food by connecting part of the stomach directly to a lower part of the small intestine.

Like any kind of surgery, there are risks associated with bariatric surgery. These can include general complications such as blood loss, blood clots, infection, and death (also called mortality). Risks are much lower with laparoscopic surgery, which uses very small incisions in the abdomen, and when the surgery is performed by an experienced surgeon in a center where weight loss surgeries are performed more often. Higher mortality rates are associated with having a higher body mass index (BMI), being older, and also having sleep apnea or diabetes mellitus. Complications after surgery may develop from gastric bands slipping out of place and needing to be re-positioned; the stomach or intestines may become blocked by scar tissue and require more surgery.

Benefits of bariatric surgery include possible remission of diabetes mellitus. One large, long-term controlled study of people with established diabetes compared bariatric surgery to conventional medical therapy for obesity. After two years, 72% of the group who had bariatric surgery had reversed their diabetes, while only 21% of the conventional group did so. Markers of inflammation such as C-reactive protein were reduced; blood lipid profiles and liver function were improved. Gastric bypass surgery appears to be very effective at resolving systemic high blood pressure; in one study 80% of surgical patients maintained normal blood pressure over a 10-year follow-up period.

The most striking finding discussed in this article is that bariatric surgery seems to help people live longer. At eight studies to date using different kinds of research designs have found that patients who have weight loss surgery consistently show reduced rates of mortality compared to those who do not, ranging from 25% to 89%

Is this study relevant to me? Yes, if you are considering the pros and cons of having weight loss surgery. Health care professionals who work with bariatric surgical candidates and patients will also find this article useful, based on its summaries of a large number of studies. 

Limitations of the study: More research is needed to determine which surgical procedures offer the best outcomes for individual patients.

Find this study in PubMed:

Bariatric Surgery and Cardiovascular Risk Factors: A Scientific Statement From the American Heart Association.

Poirier P, Cornier MA, Mazzone T, Stiles S, Cummings S, Klein S, McCullough PA, Ren Fielding C, Franklin BA; on behalf of the American Heart Association Obesity Committee of the Council on Nutrition; Physical Activity, and Metabolism.

Circulation. 2011 Apr 19;123(15):1683-1701. Epub 2011 Mar 14.

DOI: 10.1161/CIR.0b013e3182149099