Why Diets Don’t Work

After trying my share of fad diets I’ve learned they all have the same thing in common. You lose the weight and then crash and burn. In the past, these diets always consisted of cutting calories, constant hunger and a rollercoaster of numbers on the scale. This is exactly why not a single one worked, a fad is just that, an unsustainable trend. Although calorie restrictions can result in initial weight loss the majority of people who try to lose weight end up relapsing and gaining all or even more of their pounds back. Although our environment and food cultures have changed, our bodies’ physiology has not. During hunter gatherer days famines were a common occurrence. Our bodies’ physiology was driven by the ability to store fat as a protection mechanism during those times of food shortages. Placing yourself on a restricted calorie diet will result in rapid weight loss, tricking your body into thinking it is experiencing a famine. You may lose 10 pounds or so by nutritionally starving yourself, but when you stop dieting your body will need to eat, thus why most people end up gaining more weight and fat mass than they lost. ¹

A recent study published in the Obesity Journal looked at long-term sustainability of rapid weight loss of 14 Biggest Loser Contestants. The study found that 6 years after the show ended all but one participant had regained a significant amount of weight, on average ~42kg which equates to about 92 pounds. The study also found that at the 6 year follow-up, 5 out of 14 participants were already within 1% or heavier than their weight prior to being on the Biggest Loser competition. This was largely due to the effects on resting metabolic rate and hormone level changes that occur during periods of rapid weight loss.

Your resting metabolic rate (RMR) represents the amount of calories your body would burn if you were to do absolutely nothing for 24 hours, i.e. these are the calories burned by automatic body functions like keeping your heart beating and lungs breathing. When your body undergoes rapid weight loss over a short period of time your RMR slows, creating a thermogenesis adaptation response to the loss of reactive tissues. This adaptation occurs to try and counteract the sudden weight loss by reducing your energy expenditure and slowing your metabolism.  For the participants in the Biggest Loser follow-up study this meant an average RMR of 500 kcal/day lower than what is typically expected for their specific body compositions. The study also found that the participants who had the greatest weight loss in the shortest periods of time showed the greatest slowing of RMR.

Rapid weight loss due to caloric reduction dieting can also result in plummeting levels of leptin. Leptin is an adipocyte hormone that acts on the hypothalamus to control hunger and increase energy expenditure.  A study published in the New England Journal of Medicine found that during periods of caloric restriction fasting plasma levels of leptin dropped about 64%  from baseline. During the weight maintenance phase of weeks 10-62 plasma levels of leptin remained 35% below baseline. The study also found that there was a linear correlation between weight gain and leptin level increases. Meaning regain the weight, regain the leptin and that’s exactly what our bodies’ attempt to do. It is not just about falling back into bad habits, there is a physiological basis to weight gain. Rapid weight loss due to dieting can dramatically alter (or even damage!) your metabolism and make it nearly impossible for your body to burn enough calories too keep off the weight.

So does this mean that all hopes of weight loss are just that, lost? Absolutely not. The key is adding in safe and effective lifestyle changes to your diet and exercise habits. Successful weight management comes from sustainable approaches that counteract our bodies’ compensatory mechanisms to changes in things like RMR, leptin and hunger.  You can do this by approaching weight loss in steps. Studies have shown that small energy and calorie deficits over time will result in more sustainable and successful weight loss over the long-term. Permanent weight loss takes time and is a lifelong commitment, so it is crucial that we take our focus away from fast fad dieting and start focusing on lifestyle changes.

We can do this by looking at why our bodies are storing fat in the first place. Things like sleep deprivation, dehydration, stress, toxins, digestive issues, nutritional deficiencies can all cause our bodies to store fat as a protective mechanism for maintaining homeostasis. When your body wants to store fat it’s nearly impossible to lose the weight no matter what you do, so it is important to address and resolve any stressors you may have. Activities like yoga and meditation, eating healthy fats and protein, getting adequate optimal vitamin D intake and eliminating processed foods and toxins are all great examples to jump start your body into effectively losing and keeping off weight ¹.

When it comes to exercise people often see the gym as their savior from a bad diet. But the reality is spending endless hours doing cardio is not only hard on your body, but can actually hinder weight loss. Exercise smarter, not harder. Remember those lean hunter gatherers we discussed earlier? Their exercise consisted of running from predators, it was get thin or get eaten. High intensity interval training can trick your body into this “survival mode” and has been shown to be the most effective at burning fat. By also adding in resistance training to your workout regimen your body will start to gain muscle mass causing your metabolism to increase, i.e. you will burn more calories and fat overtime.

The most important thing I’ve learned from my journey to health and wellness is you need to find balance. Sure I spend hours each week sweating through circuit workouts and prebaking chicken and broccoli, but I also enjoy a good burger and craft beer out with my friends. The journey to a healthier, happier you takes time. Don’t be afraid to try new things, to push yourself, to feel pain and strength. Remember to stay motivated, celebrate small victories and embrace new lifestyle changes. Be healthy, be strong, be happy.


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