Diets are generally short-term approaches to obtain weight loss that require restriction and behaviours that are not sustainable long-term. The way most diets work is through requiring us to eat significantly less calories than we require to maintain an energy balance for our current weight (or even the weight we desire), thus resulting in weight loss. However, the issue with this is that we are left feeling hungry and obsessing about food, particularly the foods that we are deprived of whilst on a diet.
A corner stone study, 'The Minnesota Starvation Experiment, 1944-1945', explored dietary restriction on thirty six young healthy men during World War II. The intention of the study was to explore the health effects of starvation and appropriate means of dietary rehabilitation of starved prisoners of war when they returned home. The study firstly required the starvation of these men so that they could then explore dietary rehabilitation strategies. Two interesting findings came out of this research that shed light on why diets don't work.
Calorie restriction initiates the starvation response
Firstly, in the study the men were starved through a diet of two meals a day totalling 1570 calories per day. This is actually higher than most modern weight loss diets, and reinforces that when we diet we are starving our bodies to attain weight loss. Unlike most modern diets, the diet in this experiment was not nutritionally balanced. Yet the starvation response obtained in this study and associated decline in strength and energy, is what people often experience when they go on a diet, in response to a lack of caloric consumption.
Calorie restriction initiates an obsession with food and an insatiable hunger
Secondly, although the men had no prior issues with weight or food, on the starvation diet of 1570 calories per day they became obsessed with food. It is reported that they lost interest in political affairs, world events, sex and romance, and food became their overwhelming priority. Some men reported reading cook books and would stare at pictures of food with an almost pornographic obsession. This is similar to those of us who go on a diet, then started to obsess about food; and we now have the ability to watch food porn by way of cooking television shows!
Cheating became an issue among the men as they reported having an almost uncontrollable urge to seek out food. How similar is this to secret eating when on a diet or compulsive or binge eating? The hunger and obsession with food that dieting creates promotes an uncontrollable urge to eat, and unfortunately, we blame this on our motivation or stamina, when it is an underlying biological drive for survival.
The Minnesota Starvation Experiment reinforces that the deprivation and restriction required on most diets is something that most of us can only keep up for a short period of time before we 'break' our diet. Although it may be argued that the men in the study were of a healthy weight before they started and this may therefore not represent overweight individuals, dieting is prevalent in individuals who are of a healthy weight and desire weight loss to fit into that dress or maintain a weight they were when they were in their twenties.
Our insatiable hunger causes a weight rebound effect
Even if we persist with a diet, even if we succeed at it, because what we ate during the diet is frequently even less calories than required to maintain the weight we achieve, once we start eating ‘normally’ again the weight slowly creeps back on. This has been shown time and time again by countless studies and anecdotal evidence.
In the Minnesota Starvation Experiment it was found that when the men could eat unrestricted, after the experiment ended, they ate considerably more calories than they did prior to the experiment, and in some cases nearly three times than prior to experiment calorie consumption in a single day. For many months, the men reported having a sensation of hunger they couldn't satisfy, not matter how much they ate.
In support of this, a review of long-term outcomes of calorie-restricting diets found that one third to two thirds of dieters regain more weight than they lost on their diets. To add insult to injury, this review found that there is no consistent evidence of significant health improvements regardless of weight lost.
Therefore, depriving and restricting yourself is not an effective means to achieve and maintain weight loss, nor to achieve good health. In conclusion, our obsession with weight loss programs and diets is futile.
Keys A., Brozek J., Henschel A., Mickelsen O., Taylor H.L. 1950. The Biology of Human Starvation, Vols. I-II. University of Minnesota Press, Minneapolis, MN.
The Great Starvation Experiment, 1944-1945.
Men Starve in Minnesota. Life (July 30, 1945). 19(5): 43-46.
Mann T., Tomiyama A.J., Westling E., Lew A.M., Samuels B., Chatman J. Medicare's search for effective obesity treatments: diets are not the answer. Am Psychol, 2007. 62(3): 220-33.