Why undereating won’t actually help you lose weight
Many people think that the key to weight loss is the less food you eat the more weight you lose, but the truth is the key to weight loss is the opposite of this. Weight loss or weight gain is controlled by our metabolisms. Your metabolism is the process by which you body converts what you eat and drink into energy. This energy is used for everything your body does, even when you’re at rest; breathing, circulating blood, adjusting hormone levels, growth and repair of cells.
Your metabolism is influenced by your body fat, fat/muscle composition, gender, and age. When you eat very little your cells are subjected to famine, and since your cells are what makes your body run, they will do anything to survive. This includes slowing down your metabolism and storing more energy in from the food you eat. A slower metabolism burns fewer calories at rest for body functions and stores more calories in case they’re needed during starvation. The body will also start to consume its own muscle when its food deprived so it has enough energy for daily functioning, and this doesn’t take into account working out.
Let’s take a bagel for example. If you are eating enough to sustain life then your body will digest the bagel, take the energy it needs from it and excrete the rest. However, in a starvation state your body takes the carbohydrates and fat from the bagel and stores as much of it as possible because your cells don’t know the next time, they’ll get food. This causes you to gain weight. The best real-world example of this is from the show The Biggest Loser. The participants of this show were subjected to extreme workouts and low-calorie diets for 7 months. In a 6 year follow up study of the shows participants they had numerous detrimental health effects including:
Slower metabolisms: they burned fewer calories at rest each day
Gained weight back quickly once they ate normal again
Had lower levels of lean muscle then they did before the show from their body consuming muscle to survive
Had lower levels of leptin: this hormone triggers feelings of fullness so they now had a harder time determining when they were full
So, what does all this lead to?
The loss of both fat and lean muscle tissue triggers the body to actually “overshoot” and gain more weight in the form of fat for survival. This leads to a constant cycle of dieting and weight gain which only causes more stress on the body. With each diet you go on your body keeps adapting to survive making it harder for you to lose weight than previously. This is called weight cycling, and overtime becomes very dangerous for your body. The effects of this includes reduced heart muscle mass, extremely low heart rate and blood pressure, feeling cold all the time, dizziness, fatigue, hair loss, dry skin, depression, anxiety, trouble concentrating, thinking about food all the time, eating very fast or slow, binge eating.
The best way to go about weight loss is to focus on eating more. I know this sounds scary, but shifting the focus to whole foods, fresh fruits and vegetables, whole grains, healthy fats and increasing calories means you are providing your body with exactly what it needs to lose fat and gain muscle.
The actual calories vary person to person, but the main idea is that once you start working out consistently you can’t drop calories, because that will only hurt your body in the long run.
References:
Jasper Most, Leanne Maree Redman, Impact of calorie restriction on energy metabolism in humans, Experimental Gerontology, Volume 133, 2020
Josephine Connolly, Theresa Romano, Marisa Patruno, Effects of dieting and exercise on resting metabolic rate and implications for weight management, Family Practice, Volume 16, Issue 2, April 1999, Pages 196–201
Fothergill E, Guo J, Howard L, Kerns JC, Knuth ND, Brychta R, Chen KY, Skarulis MC, Walter M, Walter PJ, Hall KD. Persistent metabolic adaptation 6 years after "The Biggest Loser" competition. Obesity (Silver Spring). 2016 Aug;24(8):1612-9. doi: 10.1002/oby.21538. Epub 2016 May 2. PMID: 27136388; PMCID: PMC4989512.
