It seems that at every turn there is a new fad diet that promises to help you lose that weight you’ve been wanting to shed. But which one actually works? The answer, unfortunately, is none of them. Because diets don’t work.

Weight loss is something that comes up all the time, but to address some of the major factors surrounding weight loss it will take more than one post. So I’m going to write three; one on diets, one on hormones, and one on the bigger picture. Weight and weight loss are extremely complex issues, more complex than just calories in and calories out. So if you’ve been struggling to lose weight unsuccessfully, one of these three major issues might be the key.

Diets in the modern context

First, diets. It’s easy to lose weight (providing there are no major hormonal issues). No really, it is. In the short term. If you restrict your calories enough, you will lose weight. The problem is, that the minute you start eating “normally” again, you gain it all back. Sound familiar? This is because our bodies didn’t evolve for the modern context. Our bodies evolved to withstand drought and famine, and it can’t tell the difference between an shortage in the food supply and deciding to go on a diet. Think about it. How would your body survive a sudden shortage of food? It hunkers down, slows metabolism, and burns fat and muscle for nutrients. After the food supply picks up again, your body is thinking: “Ok. I have experienced a food shortage. I can reasonably expect that to happen again, so now that I have food I’m going to store as much as I can so that next time I can survive the food shortage.” And thus, cavemen survived to become modern day humans because they could survive inevitable droughts and famines.

Now introduce the modern context. We have an overabundance of food, at least in the Western world anyways. But every year a human decides to eat nothing but salmon and grapefruit* (please do not try, this is horribly nutrient deficient) for 6 weeks to lose those 10 pounds to get a “beach body” for their beach vacation (spoiler alert, you already have a beach body on account of having a body and going to a beach). So take those systems that have evolved to get through food shortages and add in cyclical dieting. This isn’t an unheard of concept, we call it yoyo dieting. Sound familiar? A person diets, gains all of it back and more, so diets again, and gains all of it back and more. Repeat. This is because it is programming your body (that can’t tell the difference between a diet and a famine) that it should be expecting many repeated famines, so get ready to hunker down and try to not die.

Deprivation causes weight gain

This is not just a random musing, it is most definitely supported by research. Every year science gets closer to figuring out exactly what hormones control this reaction, but the fact this is the reaction is not in question. Higginson and McNamara (2016) made a hypothetical animal model exploring how this phenomenon works. They call weight gain after periods of deprivation the insurance effect, and weight stores are less. They found that the more reliable food was before the food shortage, fat storage is predicted to be greater with dieting. Which means that the conditions which caused weight gain in the first place, or the abundance of food in the western world, predisposes us to gain more weight after diet attempts. They also found that not everyone gained weight the same way after diet attempts. They hypothesize that this is because of differing subconscious expectations about the food shortages and different genetics and epigenetics. In addition, weight gain slows as more fat is stored, which supports that people who are obese tend not to gain more weight after dieting. Which means that cyclical dieting is worse for lean people than obese people. Karl et. al. (2016) did an energy deprivation study on military personnel simulating the energy deprivation and increased expenditure they would experience in the field. These volunteers had to eat a very disgusting sounding isovolumetric food gel that was either not enough calories or enough calories for their metabolism and energy expenditure, then had a washout period, then were given the gel type they hadn’t had before. After each condition, many tests were done. They found that weight gain after an energy deficit in lean young men exceeds the amount of weight lost and is disproportionally fat (vs. muscle). There are some hormonal signals that can mediate this process, and that recovery strategies like increased protein intake after energy deprivation might help reduce the amount of fat gain and increase lean mass gain.

What works then?

Ok so we know what doesn’t work. So what does lead to long term weight loss? Montesi et. al. (2016) examined what people who lost weight and kept it off in the long term had in common over several different studies. First let’s define what successful weight loss is. I would argue (and the research does as well) that a short term reduction in weight and then gaining it all back and more is not successful, and this is what happens in a majority of people. Again, if you restrict your calories enough you will lose weight in the short term, but most people want to keep it off. A lot of the research and guidelines defines successful weight loss as losing 5-10% of body weight and keeping it off for at least 1 year. This may seem like a small amount, but it’s actually enough to create significant decreases in risk of diseases like diabetes and other obesity related disease (and increases fertility as well, incase you were wondering). The usual pattern for weight loss is a peak loss at 6 weeks and a slow reversal of the weight loss with 50% returning to their starting weight at the 5 year mark. The strategies implemented by those who maintained their weight loss for more than 5 years were: high levels of physical activity (1 hour per day), eating a low but not too low calorie diet, eating breakfast regularly, self-monitoring weight, and maintaining a consistent eating pattern across weekdays and weekends. Other individual factors associated with maintained weight loss were low levels of depression, low levels of disinhibition, medical triggers (health practitioners encouraging weight loss or having a family member suffer a heart attack), internal locus of control (believing that you control things in your life vs external uncontrollable factors), high self-efficacy and self-regulation skills, and low novelty seeking (not needing new exciting stimuli). Something else that should be considered is the impact of sleep and the circadian rhythm on weight. Short sleep duration has been associated with weight gain, and the mechanism is still a bit of mystery but it likely is impacting insulin in a negative way. Also, food intake and energy expenditure are negatively impacted by engaging in them when the body is promoting sleep (for example shift work, sorry folks). Another interesting predictive factor for maintaining weight loss is positive body image. Which means that if you already love your body as it is, you are more likely to lose weight and keep it off. Interesting, non??

Increasing muscle mass is very beneficial for long term weight loss

Putting it into action

Now that we know what people who lost weight and maintained it have in common, how can we use that knowledge to promote weight loss? What about those people who don’t have internal locus of control or positive body image? Firstly, encouraging regular, long term physical activity is a good place to start. Exercise isn’t strongly associated with initial weight loss but it is essential for keeping the weight off. Following the rest of the commonalities listed above would also be a good idea (eating a regular breakfast, eating at a slight 400 calorie deficit, self-monitoring and consistency). Another strategy that has been shown to be helpful is support groups. Long term in person or over the phone support has been shown to be more effective than online, but online can work for some people too. This is a great strategy for people who don’t have good self-motivating and self-regulating skills. For those struggling with weight loss and maintenance, pleasurable leisure time physical activity has been shown to be successful. In particular, dancing has been shown to help with weight loss. Not only is this pretty much exercise, but it’s fun, promotes social interaction, strengthens relationships in the community, and promotes healthy cognitive functioning. As discussed before, social support promotes motivation, which is important in weight loss.

To sum up, weight loss is a complex physical and psychological process. Weight loss goals should be 5-10% of current body weight (not to look like a cookie cutter swim suit model), and all aspects of health should be considered. This includes good sleep quality, good social relationships and support, mental health and mood support, as well as long term consistent improvements in diet and exercise. When we talk about weight loss, we aren’t talking about 6 weeks of starvation and grumpiness, we are talking about months of comprehensive lifestyle changes, that should be transitioned to permanent to maintain the weight loss. It won’t be a linear path either, there will be ups and downs. But overall, there will be a net loss. Your old lifestyle promoted weight gain, so you’re going to need a different lifestyle to promote weight loss.

References

• Higginson AD, McNamara JM. An Adaptive response to uncertainty can lead to weight gain during dieting attempts. Evolution, Medicine, and Public Health. 2016; 369-380.
• Karl JP, Smith TJ, wilson MA, et. al. Altered metabolic homeostasis is associated with appetite regulation during and following 48-h of severe energy deprivation in adults. Metablism. 2016; 416-422.
• McHill AW, Wright KP. Role of sleep and circadian disruption on energy expenditure and in metabolic predisposition to human obesity and metabolic disease. Obesity Rev. 2017; 15-24.
• Montesi L, Ghoch ME, Brodosi L, et. al. Long term weight loss maintenance for obesity: a multidisciplinary approach. Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy. 2016; 9: 37-46.
• Muller MJ, Enderle J, Pourhassan M, et. al. Metabolic adaptation to caloric restriction and subsequent referring: the Minnesota Starvation Experiment revisited. Am J Clin Nutr. 2015; 102: 807-819.
• St-Onge MP. Sleep-Obesity relation: underlying mechanisms and consequences for treatment. Obesity Rev. 2017; 34-39.