Buzz
After many years, I decided to count calories again in preparation for an upcoming master’s boxing match. I didn't have much to lose and wasn’t rushing, so I aimed for a modest 2,000 calories a day, hoping for a gradual reduction in weight.
Two days in, as I sat at my desk, feeling my stomach rumbling, all I could think was: “How can anyone survive on just 1,200 calories a day?” I’m in decent shape for a geriatric millennial raising a hyperactive toddler in the middle of a pandemic, but I’m definitely not an athlete.
The conventional wisdom I’ve heard all my life is that if you’re a woman trying to lose a few pounds, 1,200 calories a day is the magic number—1,500 if, and only if, you’re active. The notion that a woman might lose weight while eating 1,800 or 2,000 calories a day is almost unheard of, a feat achievable only by Olympic athletes who work out for hours every day.
The number 1,200 calories has been ingrained in my mind since I first became aware of dieting, at a far too young age. It’s the foundation of nearly every commercial diet, from the reliable, traditional WW (formerly Weight Watchers), which calculates points based on a food’s nutritional value, to Noom, the new kid on the block that has the energy of “I’m different from those other diets,” but in reality, it is still a diet that suggests consuming just 1,200 calories a day.
The 1,200-calorie suggestion dates back to the 1920s
The idea of consuming 1,200 calories a day for weight loss has been around since the 1920s, thanks to a book titled Diet and Health: With a Key to the Calories, which became popular across America. Despite 100 years of evidence showing this approach doesn’t work, the notion persists. (Another “brilliant idea” from the 1920s: adding the radioactive element radium to toothpaste, food, and drinks—until it was halted after many factory workers, mostly young women, tragically died from radium poisoning.)
These diets are rarely effective. A person may lose weight in the short-term, but the hunger becomes unbearable, leading them to abandon the diet, often regaining the lost weight—and sometimes more. “A lot of my clients have tried 1,200 calories before,” said Jamie Nadeau, a registered dietitian specializing in helping people rebuild a healthier relationship with food. “They either couldn’t stick with it, because it’s simply not enough food, or they did stick with it for a while, lost some weight, but then ended up with a poor relationship with food or gained everything back.”
There’s a reason for this: for most women, 1,200 calories a day is effectively a starvation diet. “For most women, you need more than 1,200 calories just to maintain your basic bodily functions,” Nadeau explained. “The idea that people are trying to survive and exercise on such a small number of calories is absurd.”
1,200 calories is half of what the average woman needs daily
Recent studies published in the journal Science in August reveal that the average adult woman between the ages of 20-60 burns approximately 2,400 calories a day. This is an average—smaller women or those with slower metabolisms burn fewer calories, while larger women or those with faster metabolisms burn more. According to Herman Pontzer, a faculty member at Duke University and lead author of the study, 1,200 calories a day is about half of the average woman’s needs.
Contrary to what our fitness trackers might suggest, we don’t start with a low baseline energy requirement and “earn” extra calories by moving. Instead, our bodies have evolved to expend a relatively fixed amount of energy each day, a phenomenon known as “constrained total daily energy expenditure.”
What this means is that while physical activity is important for our long-term health, including weight maintenance, it doesn’t burn as many extra calories as we tend to think, and it won’t result in weight loss unless we make a deliberate effort to reduce our food intake.
Our bodies treat daily energy expenditure as a set budget, reallocating energy to different processes to ensure the total remains the same by day’s end, only to reset and start again the next day.
When we remain inactive, our body reallocates the surplus energy to demanding processes, like our immune system and stress response. While small amounts of these processes help us ward off infections and avoid danger, large quantities can contribute to chronic diseases.
If we are highly active, such as training for an event, our bodies will burn more energy in the short run, but eventually, they will adjust, bringing our energy requirements back to a level closer to our usual daily needs.
If we gain muscle during the process, our metabolism will increase along with our daily energy needs, due to the rise in fat-free mass. Additionally, our hunger will intensify, as this is how our brain helps maintain a stable weight—a key factor in human survival throughout history.
1,200 calories a day resembles the Minnesota Starvation Experiment
Considering that the average daily energy needs of a woman is around 2,400 calories, a 1,200-calorie-a-day diet is essentially equivalent to the Minnesota Starvation Experiment, which took place in 1944 to explore the best methods for re-feeding those suffering from starvation.
For this research, 36 young, healthy men took part in a year-long experiment. The first three months were dedicated to determining the amount of food they required each day. In the following six months, they subsisted on around 1,570 calories a day, which is roughly half of what they needed. During this time, they shed about 25% of their body weight. The final three months allowed them to eat freely and as much as they wanted.
Along with the weight loss, the participants became excessively fixated on food, a preoccupation that lasted well beyond the starvation period. They also developed mental health challenges such as anxiety and depression, and their eating behaviors became similar to those seen in individuals with anorexia, bulimia, or binge-eating disorders.
The participants in the Minnesota Starvation Experiment were highly driven volunteers. They believed their involvement would benefit those suffering from starvation, while also living in a tightly controlled environment. Despite these intentions, they experienced lasting psychological issues even after the starvation phase ended.
Deprivation diets can trigger a cycle of disordered eating
In real-life situations, a person may start a 1,200 calorie-a-day diet, managing to stick to it for a few days, maybe even a few weeks, especially if they’re highly determined. However, most people eventually fall off track, eating more to compensate for the deprivation they experienced.
There’s a good possibility that individuals aren’t tracking their food accurately. As Pontzer said, “[P]eople are terrible at accurately tracking what they eat.” He explained that those attempting a 1,200 calorie diet might find themselves reducing their intake less drastically than intended.
For most people, these restrictive diets are unsustainable, meaning the weight will eventually return. Additionally, people can develop an unhealthy relationship with food during this time. Nadeau commented, “What I hear the most about 1,200 calories a day is that even if they are able to stick to it, they are miserable.”
There’s no easy answer to diet culture
When I talk about our struggles with healthy eating, I’m not just speaking about an abstract “we”—I’m including myself. Along with societal pressures, I grew up with a father who oscillated between crash dieting and binge eating. He also belittled the women in our family who weighed more than what he deemed acceptable—about 5 feet 6 inches tall and 110 pounds. My sister’s response was starvation; mine was repeated cycles of extreme dieting and emotional eating.
I’ve spent a significant part of my adult life trying to unlearn the patterns I inherited. A breakthrough came when I discovered a sport I truly enjoyed, which not only taught me about my body’s strength but also helped me understand the importance of respecting my body’s needs, including a balanced diet.
Nadeau encourages a similar mindset with her clients, advising them to cultivate habits that enhance their lives rather than depriving themselves. “You really have to take an active stance, to say that ‘I’m not going to diet anymore, I’m not going to starve myself or restrict myself for the purposes of weight loss anymore,’” Nadeau explained. She suggests focusing on positive habits that improve life, such as increasing vegetable intake, eating fiber-rich protein, or engaging in enjoyable physical activity.
This advice may sound unconventional in today’s world, but in a more balanced society, it would be considered common sense. Unfortunately, our disordered views on health and nutrition are far more widespread than many of us recognize. Even though it’s been years since I saw 1,200 calories a day as a suitable intake, I still struggle with the notion that 2,000 calories a day seems like a lot, despite knowing what my body truly needs.
Based on my body’s signals, I ended up increasing my food intake once more. Although I’m eager to compete again, which will naturally involve monitoring my weight, my top priority is maintaining strength. Though I’m still a work in progress, figuring it out along the way, one thing is certain: I’m not going to starve myself.
