Eat less, move more? Why dieting does not work
Last week we discussed the basics of metabolism. We learned what our metabolic rate is and how the different components (BMR, TEF, and movement) influence the rate at which we expend energy. This week we are going to discuss the effects of the "eat less, move more" mentality on our metabolic rate.
One study that investigated this topic followed contestants of "The Biggest Loser" for six years after being on the show. In case you are not familiar with this television show, "The Biggest Loser" selects people with a BMI greater than 30 (often a BMI greater than 40) and helps them lose weight by diet and exercise. They have personal trainers who educate them on nutrition and exercise as they compete with each other to lose the most weight and win a monetary prize. Season three winner of "The Biggest Loser", Kai Hibbard, shared that contestants of the show eat around ~1000-1200 calories/day and exercise for 4-6 hours a day, including two hours of hard-core cardio (1).
Just to compare the 1,000-1,200 calories/day diet that the contestants ate vs. their actual needs let's make up a sample contestant. Say Pollyanna was a 35 year-old woman who is 5'5", and weighs 250 lb. Her BMR is estimated to be ~1,890 calories/day. Keep in mind that this is her BMR and not her total metabolic rate. Assuming that she is not very active during her day, we will give her an activity factor of 1.3 (very light) and her total energy needs would be around 2,400-2,500 calories/day.
If she was very active, which contestants on "The Biggest Loser" are, she would need around 3,600 calories a day to maintain her weight. Obviously, Pollyanna would be trying to lose weight if she was on the show so she would need a slight calorie deficit, but certainly not a deficit of 2,400 calories/day. This large of a deficit puts the body in a state of panic. Her body thinks she is starving to death. It quickly produces changes in the body that slow her metabolism so that she does not waste away. This is exactly what happened to the contestants on "The Biggest Loser".
The study investigating the effects of "The Biggest Loser" found that after being on the show, contestants metabolic rate (TMR) was lower than predicted for someone of their current age/gender/size. This resulted in them regaining much of the weight they worked so hard to lose (2).
To demonstrate this is not just something that happens to "The Biggest Loser" contestants, here is another study done by a researcher named Apfelbaum. He studied the effect of over and under eating in individuals who were clinically obese (BMI of 30.0 or higher).
Half of the participants were put on a very strict diet (2,000 calorie deficit) and the other half ate 1,500 calories MORE a day. The group who restricted reduced their metabolic rate by 12-17% in just two weeks! The group who ate more increased their metabolic rate by 15-29% in those two weeks. At the end of the study the group who restricted were hungrier, their metabolism was slower, and they even burned less calories during exercise than before the study began. The participants in the group who ate more did gain weight (~3 lb. in two weeks), but they increased their metabolic rate and were now burning 350-400 calories/day (3).
Okay, here is one last study. Hang in there! This is a classic study from the 1940s led by Dr. Ancel Keys in Minnesota. He and his cohorts were investigating the physiological and psychological effects of starvation so that they could help people recovering from starvation during World War II. They recruited 36 young men who were deemed to be in good physical and mental health prior to the study. They were told that they needed to lose 25% of their body weight in six months time via semi-starvation.
During the six months, the participants became gaunt, lost muscle strength, had a reduced core body temperature, reduced heart rate, and decrease in their sex drive. They reported dreaming about food during the night and fantasizing about what they would eat and when (4). They also experienced a 40% decrease in their metabolic rate, which translates into burning 600 calories less each day (5).
These studies serve as an example of what happens when people aggressively pursue the "eat less, move more" diet mentality. Research shows that a decrease in metabolic rate can occur in as little as 1-2 days of undereating. The more times a person diets, the longer it takes their metabolic rate to recover afterwards.
So what now? Is it all discouraging news?
No! We can normalize our metabolic rate by supporting and nourishing our body. We do this by:
1) Eating MORE and moving LESS. We need to pull our bodies out of starvation mode that dieting caused. We do this through nourishment NOT deprivation. We move less for a period of time so that our body can focus on repairing and healing.
2) Trusting your hunger and fullness cues. You may be hungrier than normal after a period of dieting. It is okay. It will normalize.
2) Processing your fears regarding your hunger cues with a dietitian. If you have a history of eating less and moving more you likely do not trust your hunger cues. It can be scary to flip that switch. A trained dietitian can help address those fears and walk with you through this time.
3) Eat nourishing foods. As your body is healing and repairing itself after deprivation it is important to provide basic building blocks for this process. Some foods to incorporate into your diet include:
Coconut oil
Avocados
Grass-fed butter
Wild-caught salmon
Grass-fed meat
Organic, free-range poultry
Pastured eggs
Bone broth and more!
For more information or to begin this journey, contact Katie at balancednutrition4you@gmail.com. To schedule an initial assessment click on the link below:
References:
1 http://nypost.com/2015/01/18/contestant-reveals-the-brutal-secrets-of-the-biggest-loser/
2 Fothergill, E., Guo, J., Howard, L., Kerns, J,C, Knuth, N.D., Brychta, R., Chen K.Y., Skarulis, M.C., Walter, M., Walter, P.G., and Hall, K.D. (2016). Persistent metabolic adaptation 6 years after "The Biggest Loser" competition. Obesity, 24(8):1612-16129. doi: 10.1002/oby.21538. Epub 2016 May 2.
3 Apfelbaum, M., Bostsarron, K. & Lacatis, D. (1971). Effect of caloric restriction and excessive caloric intake on energy expenditure. American journal of clinical nutrition, 24: 1405-1409.
4 http://www.apa.org/monitor/2013/10/hunger.aspx
5 Keys, A. Brozek, J., Henschel, A., Mickelson, O. & Longstreet, T. (1950). The biology of human starvation. Vols. 1 and 2. Minneapolis, MN: University of Minnesota Press.
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