Posts Tagged ‘weight loss’

Where is Your New Year’s Resolution? Or, Where did I put my Adaptive Thermogenesis?

January 17th, 2014

It’s mid-January: do you know where your New Year resolution went? You know the one about losing weight.

So maybe you are losing the weight you put on over the holidays? Maybe you are underway with a good weight loss program? Maybe you have already given up? No matter what your status, there is something you should know:

The human body is programmed to defend its weight and, when it senses weight loss, it starts cutting down its energy expenditure…big time!

Let’s talk about energy expenditure or “EE”. About 65-70% of calories burned each day are used to keep the routine body functions going, e.g. pumping blood, working the lungs, kidneys and liver. About 10% are used up in thermogenesis or the digestion of food. The rest, about 20%, is spent by the muscles in physical activity.

As far back as 1987, researchers compared the daily resting metabolic rate (RMR) of obese women who had lost weight and were no longer obese with women who were  never obese. The researchers found that the post-obese women had metabolic rates approximately 15% lower than the never-obese group and they ate less.

So, metabolism in persons who have lost weight and those who are lean may not be the same.

Exercise and the heat value of food are skewed against those with obesity. In one experiment, 10 lean women and 10 women with moderate obesity were measured during periods of eating and exercise. Eating before exercise increased the exercise metabolic rate in lean women by 11% but only by 4% in women with obesity. The thermic effect of food was 2.54 times greater during exercise than at rest for the lean group, but only 1.01 greater for the women with obesity.

In a now classic 1995 paper by Jules Hirsch, Rudy Leibel and Michael Rosenbaum at Columbia University found that when a body loses weight, it adjusts by reducing its energy expenditure. This effect is so strong that an obese person who went from 250 lbs to 200 lbs would have to consume about 30% less than a 200 lbs person who had not lost weight just to maintain the same weight. This extra-reduction in food intake would have to continue indefinitely if the person were to maintain their weight loss.

This process, called by researchers “Adaptive Thermogenesis” can persist after active dieting for up to a year in one study.  In an experiment involving subjects with severe obesity who were on a program of diet restriction and vigorous physical activity, researchers saw dramatic weight loss (over 30%) but a slowing of the resting metabolic rate (RMR) “out of proportion to the decrease in body mass, demonstrating a substantial metabolic adaption.”

Some researchers considered adaptive thermogenesis a major factor in the plateauing one sees in dieters, the increase in hunger and the eventual regain of lost weight. In one study of short-term severe diet and exercise subjects, the ‘metabolic compensation’ was seen as a major contributor to the less-than-expected weight loss. Individuals will have different adaptions to weight loss. In some cases, the effect can be significant. Tremblay et al state, “Indeed, as it is difficult to prescribe food intake that imposes an energy deficit exceeding 700-800 kcal per day to obese individuals, the decrease in energy expenditure in response to weight loss can entirely compensate for this prescribed deficit.”

Others are less sure. They seem to accept adaptive thermogenesis but see measurement problems and questions as to its utility in weight management.

The point is that our bodies contain a defensive mechanism against the disease of obesity. Until we realize that our strategies for prevention and treatment are like a novice chess player going up against a Grand Master. The point is: obesity is a lot tougher than our simplistic policy prescriptions assume.

The quandary of obesity has been expressed by Tremblay Chaput and Doucet in their article “Obesity: a disease or a biological adaption? An Update,“ Additionally, substantial body fat loss can complicate appetite control, decrease energy expenditure to a greater extent than predicted, increase the proneness to hypoglycaemia (low blood sugar) and its related risk towards depressive symptoms, increase the plasma and tissue levels of persistent organic pollutants that promote hormone disruption and metabolic complications, all of which are adaptations that can increase the risk of weight regain. In contrast, body fat gain generally provides the opposite adaptations, emphasizing that obesity may realistically be perceived as an a priori biological adaptation for most individuals. Accordingly, prevention and treatment strategies for obesity should ideally target the main drivers or root causes of body fat gain in order to be able to improve the health of the population.”

 

Results of Look Ahead Published

June 26th, 2013

As indicated on October 22, 2012, the Look Ahead trial was stopped early on the basis of futility. Now, we have the results of the study in the New England Journal of Medicine, June 25, 2013. The trial was a long-term study of intensive lifestyle intervention for weight loss to see if that would decrease cardiovascular morbidity and mortality among patients with type 2 diabetics. After 9.6 years, the study was stopped. While weight loss was greater in the intervention group than in the control group (6.0% v. 3.5% at study end), the intensive weight loss did not reduce the rate of cardiovascular events. The lifestyle intervention did reduce HbA1c, improve fitness and all cardiovascular risk factors except for low-density lipoprotein cholesterol levels. In addition, earlier reports indicated that the lifestyle group was more likely to have a partial remission of diabetes during the first 4 years of the trail than those in the control group and also showed reductions in urinary incontinence, sleep apnea, and depression and improvements in quality of life, physical functioning and mobility.

 

Patterns of Weight Loss in Look AHEAD

December 5th, 2012

While the Look AHEAD trial has been suspended,  it much information to yet give up.  In a paper in Obesity, the Look AHEAD Research Group reports that 2 components of the Look AHEAD program accounted for about 95% of the total variability in weight loss patterns. They looked at two patterns of weight loss. The first is a relative large, early weight loss, followed by long period of maintenance. The second pattern is a more gradual, slower weight loss over a longer period of time.  They found that participants with greater month-to-month weight losses during year 1 had significantly better levels of HbAc and HDL-cholesterol at year 4, even after controlling for medications. Gradual weight loss produced better weight loss maintenance but no additional benefits. The paper did not link weight loss with specific strategies used in the interventions in Look AHEAD nor did it look at the genetic factors.    PubMed: Patterns of Weight Change in Look AHEAD Study

 

Genetic Variations Affect Weight Loss, Regain, Eating Behavior

May 1st, 2012

The Diabetes Prevention Program (DPP) is a highly publicized study comparing lifestyle intervention against metformin in preventing type 2 diabetes. It has been widely used by public health authorities to promote lifestyle changes over drugs in addressing obesity and type 2 diabetes. Delahanty LM and colleagues looked at genetic polymorphisms for an effect on short term and long term weight loss and weight regain. They found that the Ala allele at PPARG (think of this as the longitude and latitude for a gene variation) was associated with short term and long term – weight loss regardless of treatment. This study adds to the literature that genetic information can help identify those who can are more likely or less likely to benefit from intervention. PubMed:Genetic Predictors of weight loss, regain DPP

In a another trial, Look AHEAD, another obesity related risk allele at FTO rs1421085 significantly predicted more eating episodes per day. Variants within BDNF were significantly associated with more servings of dairy, meat, eggs, nut and beans. Another allele was associated with a significantly lower percentage of energy from protein. PubMed:Genetic alleles and dietary intake in Look AHEAD trial

 

FDA Approves Once Weekly Drug for Diabetes; Shows Weight Loss

January 28th, 2012

The Food and Drug Administration has approved Amylin Pharmaceutical’s Bydureon for thetreatment of type 2 diabetes. This is the first once-weekly treatment for type 2 diabetes. It is hoped that this feature will lead to higher adherence to the treatment regimen, although as with Byetta, it is injectable. The drug is exenatide, a GLP-1 receptor agonist. Study results showed an improvement in glycemic control.  A1C levels, a measure of blood sugar, decreased an average of 1.6 points.

Many patients with Type 2 diabetes are also overweight or obese. Many drugs for type 2 diabetes actually cause weight gain. The advantage of Bydureon (and its daily administered counterpart, Byetta) is that patients taking Bydureon can achieve weight loss, in addition to improvements in glycemia, blood pressure, and cholesterol in both overweight and obesity subjects with and without type 2 diabetes. Effects of glucagon-like peptide-1 receptor agonists on … [BMJ. 2012] – PubMed – NCBI

A very small study of 12 children and adolescents with extreme obesity also showed significant improvements, suggesting the need for a larger study. Exenatide as a weight-loss therapy i… [Obesity (Silver Spring). 2012] – PubMed – NCBI

More information is available at www.BYDUREON.com.

New Analyses Cast Doubt on Fruits, Vegetables, Physical Activity to Control Obesity

July 24th, 2010

July 24, 2010

A review of the relationship between fruit and vegetable intake with adult and childhood obesity casts doubt on how strong is the relationship with weight management. The review was undertaken by TA LeDoux and colleagues from the Department of Pediatrics at the USDA/Agricultural Research Service Childrens’ Nutrition Research Center at Baylor College of Medicine.

They found that, after reviewing 772 studies, increased food and vegetable consumption (in conjunction with other behaviors) contributed to reduced adiposity among overweight or obese adults but no association was shown among children.

While the quality of the studies varied widely, the relationship between high fruit and vegetable consumption and low obesity among “was weak” and among children “unclear.”

The study can be accessed at Relationship of fruit and vegetable intake with ad… [Obes Rev. 2010] – PubMed result

In a separate study, doctors in Plymouth, United Kingdom following 202 children for 7 to 10 years, found that overweight preceded physical inactivity, not the other way around.  As most childhood obesity interventions assume inactivity precedes obesity, this study, if validated, indicates a change in strategy to combat childhood obesity. See Fatness leads to inactivity, but inactivity does n… [Arch Dis Child. 2010] – PubMed result

Goals

September 27th, 2009

5-10% is a realistic and achievable goal for weight loss Weight-loss outcomes: a systematic review and meta…[J Am Diet Assoc. 2007] – PubMed Result

What interventions should we add to weight reducin…[J Hum Nutr Diet. 2004] – PubMed Result

The weight stability approach Obesity in primary care: evidence for advising wei…[Br J Gen Pract. 2008] – PubMed Result

Do physicians support 5-10% reduction? What do physicians recommend to their overweight a…[J Am Board Fam Med. 2009 Mar-Apr] – PubMed Result

Look Ahead trial shows promising results from intensive weight loss counseling One-year weight losses in the Look AHEAD study: fa…[Obesity (Silver Spring). 2009] – PubMed Result

5% reduction needed to improve metabolic parameters Degree of weight loss required to improve adipokin…[Metabolism. 2009] – PubMed Result