Can Eating Pulses Help You Lose Weight?
Pulses (non-oil seeds of legumes such as beans, lentils, chickpeas, and dry peas) are known for their high content of protein and fibre. Now a study by Kim and colleagues from the University of Toronto, published in the American Journal of Clinical Nutrition suggests that dietary pulse consumption may indeed lead to a modest reduction in body weight. The researched performed a systematic review and meta-analysis of 21 randomized controlled trials on the effect of pulse consumption on body weight, waist circumference, and body fat. Pooled analysis that included data from over 900 subjects showed an overall significant weight reduction of about 300 grams in diets containing dietary pulses (median intake of 132 g/d or ∼1 serving/d). Thus, the authors conclude that inclusion of dietary pulses in a diet may be a beneficial weight-loss strategy because it leads to a modest weight-loss effect even when diets are not intended to be calorically restricted. Exactly how and why pulses have this effect is unclear although it may well be related to their protein or fibre content. I would not be surprised if someone is already studying the effect of pulse consumption on the gut bacteriome. @DrSharma Edmonton, AB
Overview of Obesity Management in Primary Care
Given the vast number of individuals who could potentially benefit from effective long-term obesity management, there is no option but to manage most of this problem in primary care settings. While this approach can be highly effective, it does require training, resources and ongoing (lifelong?) interventions (not unlike most other chronic diseases). Now a rather comprehensive paper by Soleyman and colleagues from the University of Birmingham, Alabama, published in Obesity Reviews provides an overview of obesity management in primary care. As readers are well aware, our body weight are tightly regulated by a complex neuroendocrine system and defends us agains weight loss through a multi-faceted physiological response to prevent further weight loss and restore body weight. As the authors note, “To maintain weightloss, individuals must adhere to behaviours that oppose these physiological adaptations and the other factorsfavouring weight regain. However, it is difficult for peoplewith obesity to overcome physiology with behaviour over the long term. Common reasons for weight regain include decreased caloric expenditure, decreased self-weighing frequency, increased caloric intake, increased fat intake and eating disinhibition over time.” The paper provides a succinct overview of the evidence supporting behavioural, medical and surgical obesity treatments. It also reiterates the basic principles of obesity management as outlined in the various guidelines: 1. Obesity is a chronic disease that requires long-term management. It is important to approach patients with information regarding the health implications. 2. The goal of obesity treatment is to improve the health of the patient, and it is not intended for cosmetic purposes. 3. The cornerstone of therapy is comprehensive lifestyle intervention from informed PCPs or other healthcare professionals. 4. The initial goal of therapy is a weight loss of 5–10% in most patients, as this is sufficient to ameliorate many weight-related complications. However, weight loss of ≥10% may be needed to improve certain weight-related complications, such as obstructive sleep apnoea. 5. Consideration should be given to the use of a weight-loss medication or possible bariatric surgery, as the addition of these treatment modalities to lifestyle therapy can promote greater weight loss and maintain the weight loss for a longer period of time. 6. It is important for clinicians to evaluate the patient for weight-related complications, that can be improved by weight loss, and to consider such patients for more aggressive treatment. These recommendations (with minor variations) are also very much in line with the 5As of Obesity Management framework… Read More »
Review: Very Low Calorie Diets For Weight Loss
The term “very low calorie diet” (VLCD) refers to diets that provide <800 kcal a day with high levels of protein and minimal carbohydrate to encourage weight loss with minimal loss of lean tissue and supplemented with vitamins, minerals, electrolytes and fatty acids to ensure adequate nutrition. Such diets are almost impossible to concoct using regular foods, which is why they are generally offered as a liquid “formula” diet. Although such diets have been used for almost 100 years, they are are not usually recommended for routine weight management because of potential medical complications. When used they should always be medically supervised by health professionals familiar with their use. While medically supervised VLCDs are often the safest way to rapidly induce a substantial weight loss where needed (e.g. in a patient with severe obesity needing to lose large amounts of weight for an urgent surgical or diagnostic procedure), these diets continue to be used as a more general approach to weight management. Now, Parretti and colleagues, in a paper published in Obesity Reviews, provide a systematic review and meta-analysis of the clinical effectiveness of VLEDs in randomised controlled trials. Their analysis included 8 papers, which describe 12 randomized controlled trials comprising 14 VLCD intervention arms and 12 control arms of at least 12 month duration. The 12 trials randomized 522 adult participants to VLCD and 452 adult participants to a comparator programme. The majority of participants were women (median 71%) and median baseline BMI 38.2 kgm2. The median duration of the VLCD intervention was 10 weeks after which patients received varying amounts of further support. Overall, the difference in weight loss between the VLCD and control arms at 12 months was about 4 Kg, a difference that shrank to less than 1.5 Kg at 24 and 38-60 months. Discontinuation rates overall approached 20% in both VLCD and control arms. The only major complication reported was one case of cholecystitis leading to a cholecystectomy in the VLCD arm. There was also a significantly higher incidence of transient hair loss in the VLCD group (49 vs. 8%). The majority of the events reported were transient effects such as tiredness, dizziness and cold intolerance. From their analysis the authors conclude that, “…this review provides strong evidence that current prohibitions on use [of VLCDs] are unnecessary and provide reassurance that routine use in specialist obesity clinics should be considered when behavioural treatments alone have not produced sufficient weight loss.” “However,… Read More »
Reduced Brain Impact of Eating in Obesity
Countless studies now show that there are important metabolic differences between people living with obesity and those living with normal weight. Of particular interest are studies showing difference in hormonal and neuronal response to eating. Now, a study by Nancy Puzziferri and colleagues from the University of Texas, published in OBESITY, show that the brain response to eating may differ substantially between people with normal weight and those living with obesity. The study was conducted in 15 women with severe obesity and 15 age-matched lean women (18-65 years old). When fasting, brain perfusion measured by arterial spin labeling was similar between obese and normal-weight volunteers and both groups showed significantly increased activity in the neo- and limbic cortices and midbrain activity in functional magnetic resonance imaging (fMRI). However, after a standard meal, the lean group showed significantly decreased activation in these areas, whereas the group with severe obesity showed no such decreases. In line with these findings, after eating, subjective appeal ratings of food decreased in lean but not in the obese women. As the researchers note, these findings are in line with previous brain imaging studies. “…after eating, participants with severe obesity maintain activation in the midbrain, one of the most potent reward centers. Thus, once satiated after eating, participants with severe obesity continue to perceive food as appealing and their brains continue to be activated by visual food cues as though they were hungry.” These finding would explain why individuals with obesity are perhaps at a far greater risk to continue eating (especially highly-palatable foods such as dessert) even when satiated. What these type of studies do not tell us whether these differences are primary (i.e. could have led to the weight gain in the first place) or secondary (i.e. the consequence of weight gain). Be that as it may, the findings do show that there are significant differences in how the brain responds to eating between people with obesity and those with normal weight. Clearly, the next step would be to see if this lack of response can be restored through weight loss (e.g. bariatric surgery) or through anti-obesity medication. At least the findings perhaps explain why simply telling people with an activated limbic system to “push away from the table” may not be all that effective. @DrSharma Edmonton, AB
Chewing Gum For Dessert Burns Calories?
The answer is yes, but before anyone gets too excited, the range of extra calories burnt with 15 mins of chewing is about 6-11 kcal. These are the findings from a rather interesting study by Yuka Hamada and colleagues from Tokyo, published in OBESITY, which actually studied the effect of fast vs. slow chewing (with or without 15 mins of gum chewing after the meal) on substrate utilization, splanchnic blood flow and diet-induced thermogenesis. The 12 healthy normal-weight males, on four different days, were asked to chew a 621-kcal test meal for as long as possible as many times as possible in the slow-eating trials, while they consumed the same meal as rapidly as possible in the rapid-eating trials. In the gum–chewing trials, the subjects chewed a 3-kcal gum for 15 min after the meal. In the non-gum–chewing trials, they consumed 3 kcal of sugar with the test meal instead of chewing the gum. With both slow eating (~650 chews) and fast eating (~235 chews), gum chewing added about 850 chews to the eating episode. In both cases, the additional chewing of gum added about 6-11 extra calories to post-prondial thermogenesis (largely due to increased protein oxidation), an effect that lasted about 45 minutes after the meal (so well into after the actual chewing). Gum chewing did not change splanchnic blood flow. As the authors note, the gum chewing increased post-prandial thermogenesis in the fast meal but this increase was not greater than the additional calories burnt from chewing with the slow meal. Thus, while you would actually burn the most extra calories by eating as slow while chewing each bite as often as possible, this may be hard to do in real life (chewing habits are notoriously difficult to change). You’re second best bet would be to add 15 mins of gum chewing after the meal, especially when you inhaled our food. Will this help you lose weight? Probably not – but a few extra calories burnt everyday may well ward off weight gain (although just how much, is anyone’s guess). If you have any experience with how gum chewing has affected your eating behaviour, I’d love to hear about it. @DrSharma Edmonton, AB
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