By Madeleine Ortiz
If we are trying to lose weight, our first instinct may be to cut calories. The authors of the new Canadian Adult Clinical Practice Guidelines for Obesity, published in August 2020, spent years reviewing research about the best ways to lose weight and keep it off for good. They have concluded that for most people, low calorie diets (1200 calories a day or less) will end up doing more harm than good. So before downloading the latest calorie tracking app and setting a strict calorie goal, read why less calories might not really be the solution when it comes to weight loss.
Weight loss is not linear.
You’ve probably heard that 3500 calories equal a pound. If that’s true, it seems logical that cutting 500 calories a day from your diet would lead to a steady weight loss of one pound per week. Unfortunately though, this isn’t the way weight loss works. “Weight loss is not linear,” the guidelines state. As you lose weight, your body (through changes to your metabolism and hormones) begins to adjust and after a while you’ll need to cut additional calories in order to maintain the weight loss… and additional calorie cutting is virtually impossible when you’ve started out a restrictive daily limit.
Weight regain is common.
Even if you have obesity or excess weight, your body views weight loss as a threat and is programmed to fight back. When you start to lose weight, your body naturally produces hormones that increase appetite. In fact, research has shown that on average, appetite increases by about 100 calories a day per kilogram of weight lost. The guidelines warn that though calorie restriction will lead to short term (6-12 months) success, those results are not sustainable over time.
Those on low calorie diets are more likely to binge eat.
According to the guidelines, incidents of binge eating (or eating very large amounts of food past the point of fullness in one sitting) increase in those on low calorie diets. These binges can impair digestive and metabolic health, and lead to increased weight gain over the long term. Additionally, those with binge eating disorders often have a higher occurrence of anxiety and/or depressive disorders.
Caloric restriction is linked to disordered eating.
In addition to binge eating, the guidelines cite a review that found the development of disorders such as bulimia, anorexia and body dysmorphia (excess focus on a flaw in your appearance) was associated with a history of intentional caloric restriction for weight loss. These disorders can lead to poor health, decreased quality of life and in some cases higher risk of death.
There are negative consequences for skeletal health and muscle strength.
Quality of life is closely associated with balance and mobility, and balance and mobility are directly impacted by skeletal or bone health and muscle strength. That’s why the guidelines say it’s not a good thing that low-calorie diets are sometimes linked to decreased skeletal health and muscle strength. For some people, low-calorie diets are even associated with a type of obesity associated with loss of muscle.
There is an increased risk for malnutrition.
Many people who attempt low calorie diets end up with micronutrient deficiencies including, but not limited to, low levels of Vitamin D, B12 and iron. These deficiencies can lead to lessened mental health and weakened immunity. And unfortunately, the more restrictive the diet, the more likely you are to be at risk.
If low calorie diets aren’t the answer, how can I lose weight?
Our biology makes weight difficult to regulate and therefore the guidelines encourage you to try and take weight out of the equation and focus on health instead. We don’t control where the scale ends up, but we can choose the habits that will contribute to good health. There are many behaviors you can focus on, but the guidelines recommend choosing ones that will fit into your budget and your lifestyle over the long term. Some suggestions they include are increasing physical activity, eating more fiber, replacing ultra-processed foods with whole foods and /or taking time for mental health. Focusing on behaviors you can control (as opposed to weight loss) has been shown to improve metabolic and total health, as well as increase quality of life more (and for longer) than any restricted calorie diet. Talk to your doctor or other healthcare professional about a medical nutrition treatment plan that will be sustainable and beneficial for you.
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