The Effect of Ingested Macronutrients on Post-Meal (Postprandial) Ghrelin Response: A Critical Review
Ghrelin is a powerful orexigenic gut hormone with growth hormone releasing activity. It plays a pivotal role for long-term energy balance and short-term food intake. It is also recognized as a potent signal for meal initiation. Ghrelin levels rise sharply before feeding onset, and are strongly suppressed by food ingestion. Postprandial ghrelin response is totally macronutrient specific in normal weight subjects, but is rather independent of macronutrient composition in obese. In rodents and lean individuals, isoenergetic meals of different macronutrient content suppress ghrelin to a variable extent. Carbohydrate appears to be the most effective macronutrient for ghrelin suppression, because of its rapid absorption and insulin-secreting effect. Protein induces prolonged ghrelin suppression and is considered to be the most satiating macronutrient. Fat, on the other hand, exhibits rather weak and insufficient ghrelin-suppressing capacity. The principal mediators involved in meal-induced ghrelin regulation are glucose, insulin, gastrointestinal hormones released in the postabsorptive phase, vagal activity, gastric emptying rate, and postprandial alterations in intestinal osmolarity.
The prevalence of obesity has continued to increase over the last several years in the United States. Per the National Health and Nutrition Examination Survey (NHANES) for the 2007-2008 year, the prevalence of obesity, defined as a body mass index (BMI) = 30?kg/m2, among adults was greater than 30% and those who were overweight or obese (BMI = 25?kg/m2) was almost 70% for both men and women. The trend over the past 20 years has shown an increase in the prevalence of obesity of six to seven percent every 10 years . In addition, health care costs are approximately 42% higher for obese patients when compared to normal-weight patients .
Experience with the Use of Sympathomimetic Agents Like Sibutramine (Meridia) for Weight Loss: Mostly Negative
Sibutramine is the most recent drug with sympathomimetic activity that has been recognized by regulatory agencies as having cardiovascular adverse effects that may outweigh its potential value as a weightloss drug. Sibutramine is marketed in Europe under several trade names, including Reductil, Reduxade, Ectiva, Sibutral, Zelium, and others. Meridia is the only brand name in the United States. The European Medicines Agency took definitive action on January 21, 2010 in advising against the continued prescribing of the drug, and Abbott Laboratories suspended sales of the drug in Europe . This action was prompted by a preliminary evaluation of results from the Sibutramine Cardiovascular OUTcome (SCOUT) trial reported by the United States FDA . The FDA has not imposed a ban on the drug but has obtained a change in the boxed warning label to contraindicate its use in patients with a history of cardiovascular disease and in all individuals over 65 years of age (updated warning, April 15, 2010). These regulatory actions were prompted by an early review of the SCOUT trial  that revealed an incidence of cardiovascular events of 11.4% in patients receiving sibutramine compared to 10% in those receiving placebo. This was an unexpected finding; the hypothesis in the design of the study was that an anticipated weight loss from the use of sibutramine would be associated with a reduction in the incidence of cardiovascular events when compared to that observed in patients receiving the placebo treatment .
WEIGHT LOSS POP QUIZ: What are 3 things that ALL 8 of these advertisements have in common?
- “Burn 30 lbs in 3 weeks - no diet!”
- “Lose 9 Pounds Every 11 Days!”
- “Lose a pound a day without diet or exercise!”
- “Lose 2 pounds a day without dieting!”
- “Lose 30 pounds In 30 Days!”
- “Lose 20 lbs in 3 weeks!”
- “Burn 30 lbs in 25 days!”
- “Lose 10 Pounds This Weekend!”
Continue Reading » The Truth About Fast Weight Loss
Abstract: The objective of the following meta-analysis was to determine what kind of treatment, or combination of treatments, has the greatest effect on weight loss in overweight and obese adults.
A systematic search was conducted of the available literature published between 1993 and 2006 that covered randomized controlled trials on overweight and obese subjects who underwent treatment consisting of physical exercise and/ or changes in diet. The scope of the search thus incorporated seven relevant databases. Using 6,545 key word combinations, the electronic search yielded a total of 36,869 abstracts. 13 relevant studies with a total of 826 subjects (BMI > 25; 17 - 68 years of age) met the meta-analysis criteria. The courses of treatment included “diet (d)”, “physical exercise (pe)”, “diet and physical exercise (dpe)”, and “no intervention (ni)”. The results confirmed the hypothesis that the combined intervention “dpe” had the greatest effect with regard to weight loss. The single treatments “pe” and “d” also led to weight loss, with “d” having a significantly greater effect than “pe”. The main reason for the small sample size of thirteen studies out of 36,819 was that the experimental design and/or procedures of most studies were inadequate. A common error was a failure to assign subjects randomly to the different treatment groups. The results of our meta-analysis indicate that a combination of diet and physical exercise is the best form of treatment to induce weight loss in overweight individuals in the first weeks, followed by physical exercise to maintain weight loss.
Sugars are a ubiquitous component of our food supply. They are consumed as a naturally occurring component of our diet and as additions to foods during processing, preparation, or at the table. A healthy diet contains at least some amount of naturally occurring sugars, because monosaccharides, such as glucose and fructose, and disaccharides, such as sucrose and lactose, are integral components of fruit, vegetables, dairy products, and many grains . Sugars also add desirable sensory effects and promote enjoyment of foods. Over the years, however, sugar intake has been claimed to be associated with several diet-related chronic diseases: diabetes, CVD, obesity, dental caries, and hyperactivity in children [2,3]. One of overwhelming concerns regarding sugars is the potential for excess energy intake from sugars resulting in weight gain and displacement of more nutrient-dense foods . However, little attention has been given to the contribution of sugar and carbohydrates to total energy intake.
Effect of Point-of-Purchase Calorie Labeling on Restaurant and Cafeteria Food Choices: A Literature Review
Eating away from home has increased in prevalence among US adults and now comprises about 50% of food expenditures. Calorie labeling on chain restaurant menus is one specific policy that has been proposed to help consumers make better food choices at restaurants. The present review evaluates the available empirical literature on the effects of calorie information on food choices in restaurant and cafeteria settings.
The prevalence of overweight and obesity has increased. A strong environmental factor contributing to the obesity epidemic is food portion size. This review of studies into the effects of portion size on energy intake shows that increased food portion sizes lead to increased energy intake levels. Important mechanisms explaining why larger portions are attractive and lead to higher intake levels are value for money and portion distortion. This review also shows that few intervention studies aiming to reverse the negative influence of portion size have been conducted thus far, and the ones that have been conducted show mixed effects. More intervention studies targeted at portion size are urgently needed. Opportunities for further interventions are identified and a framework for portion size interventions is proposed. Opportunities for intervention include those targeted at the individual as well as those targeted at the physical, economic, political and socio-cultural environment.
Continue Reading » Portion Size: Effect on Food Intake and Possible Interventions
More and more, everyone is learning that "diets" don't work. Sure, people drop weight on diets but they fail to make a lasting change. I don't need to go into this, you know all about yo-yo dieting. Despite this there are still plenty of judgmental folks (who probably wouldn't know a problem if it bit them in the tuchus) who will say stuff like, "jeez, what ever happened to old fashioned self-control?"
Continue Reading » Self Control: Not all its Cracked Up To Be
While environmental and situational cues influence food intake, it is not always clear how they do so. We examine whether participants consume more when an eating occasion is associated with meal cues than with snack cues. We expect their perception of the type of eating occasion to mediate the amount of food they eat. In addition, we expect the effect of those cues on food intake to be strongest among those who are hungry.
Continue Reading » When Snacks Become Meals: How Hunger and Environmental Cues Bias Food Intake