But that's not what I say. And here's why.
But here's a cruel fact for you: decades of studying has shown that dieting does neither of those things.
Let's start with looking better. Obviously in the context of dieting that is judged on whether we got thinner or not.
Dieting can make people thinner for 6-24 months, which is how long most studies follow people. But here are some sobering realities when it comes to whether dieting even results in weight loss:
- After five years or more the success of a diet is down at about 5%, regardless of diet
- Dieting nearly always makes people heavier over time (one study as an example)
- Dieting can lead to binging behavior for long after
- Weight gain increases the number of fat cells in our body. These never go away. They just get smaller with weight loss, making it easier to gain weight again by filling out the existing fat cells.
- Its tougher to drop weight each time because dieting may lower the body's metabolism semi permanently (source)
Not only this, but the typical American tries several times each year to diet. What often accompanies this is weight cycling, or yo-yo dieting. This means body weight goes up and down. Weight cycling can be a major issue, for a variety of reasons:
- Weight cycling is correlated with more heart disease, impaired immune function, cardiometabolic risk, insulin resistance, triglycerides, hypertension, and abdominal fat accumulation
- One study on weight cycling in Japan found that women who dieted and then got back to the initial weight saw the following impacts on their bodies: resting metabolic rates dropped, lean body mass dropped but with more body fat equaling out to same weight, blood pressure and triglycerides rose.
- Another study found it correlated with higher drive for thinness, lower body satisfaction, and lower self esteem.
- Other studies find weight cycling can be connected to disordered eating, higher stress, lower well being, less confidence about food and eating
But what about health? Surely dieting and weight loss leads to better health! Sadly no. Here's what actually happens:
- According to Janet Polivy, a top researcher at UCLA, dieters tend to be more emotional and react more strongly than non-dieters to upsetting events, maybe because dieting itself creates so much stress. They have higher levels of cotrisol and free fatty acids, which signal stress. One reason is food cues one: surrounded by stimulation of any of the five senses by foods we can't have often leads to stress.
- A review 16 long-term international studies in 1987 found overweight and obesity were not major risk factors for death or heart disease. Mortality rates were in fact lowest in the overweight category of the BMI index (Katherine Flegel also documented this in 2013)
- One study done by Janet Tomiyama and Traci Mann tracked 5 common health markers: total cholesterol, triglycerides, blood pressure, and fasting blood glucose. They found no relationship between any health outcome and the amount of weight lost or gained
- The Look AHEAD study asked whether weight loss could help those with type 2 diabetes. It found no significant difference between control and variable group for heart attacks, strokes, cardiovascular issues, and premature deaths.
So in sum we can make the following conclusions: diets neither makes us thinner nor healthier, nearly everyone who diets ends up heavier in the long run, many people's health suffers rather than improves, repeated dieting can make it worse, and dieting is a major risk for binge eating and obesity. For more on this, check out Harriet Brown's fabulous book, Body of Truth.
And what do I say as a whole person running coach? I say that perhaps its time to rethink our assumptions about body, health and weight. Perhaps its time to explore our relationship with our body and with eating. Perhaps dieting doesn't need to be an automatic thing we think we should do.