We hear about obesity and overweight almost every day in mainstream media. Moreover, the web is full of articles with advice on weight loss. Despite all that, a majority of people attempting to lose weight struggle to maintain the initial loss in the long run. Often we think it is the lack of will power on the part of the individual. While there might be some truth to the individuals' responsibility, it is far too simplistic to assume there are no other factors at play. I too have experienced the difficulties of maintaining the initial loss and the constant yo-yo that goes with it. If you are like me, then the article "Why Weight Loss Maintenance Is Difficult" written by Alison B. Evert & Marion J. Franz, makes interesting reading.
Evert and Franz reviewed a range of studies related to biological mechanisms that make weight loss maintenance difficult. Approximately 50% of weight variance is determined by genetics and the balance 50% by the environment (energy-dense foods and reduced physical activity). Here are some excerpts from their study.
Genetics
"Large-scale genome-wide studies have identified nearly 150 genetic variants significantly associated with cross-sectional measures of BMI, waist circumference, or obesity risk in multiple populations". Despite the fact that we are aware of these genetic variants clinicians are yet to decide clear intervention plans for those who are at higher risk.
Hormonal Adaptations to Weight Loss
Body weight is tightly regulated by hormonal, metabolic, and neural factors. Reducing food intake leads to a negative energy balance that triggers a series of central and peripheral compensatory adaptive mechanisms designed to prevent starvation. Some of those triggers make it difficult to maintain the initial loss and often drive towards weight gain.
Neural Factors
Obesity is often associated with an increased preference for, and consumption of, foods high in fat and sugar. These could be driven by factors such as neural dopamine. With weight loss, a decrease in rewards from food intake occurs, resulting in neural dopamine signalling that drives an increased consumption to make up for the deficit.
If you are interested in reading the full article, follow this link and request the full text - http://spectrum.diabetesjournals.org/content/30/3/153. It is certainly worthwhile to understand the complexities of maintaining weight loss.
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