Obligatory disclaimer: I am not a medical doctor, and the content of this website was created for informational purposes only. Such content is not intended as a substitute for medical advice, treatment or diagnosis.
Starvation mode is a common term in the weight loss, fitness, and health communities. It is also, however, often misused and misunderstood because it is seldom defined. Consider the next quote by Priscilla Tang, which was selected due to its reach, and influence, based on its position on a Google search.
If you eat less than your resting metabolic rate, your body goes into starvation mode, thinking you are actually starving and experiencing a shortage of food and nourishment. It then slows down your metabolism to keep you alive in this state of uncertainty, not knowing when to anticipate your next dose of energy.
Taking that quote at face value, would skipping breakfast put me in starvation mode? Perhaps skipping breakfast and having a light lunch? Am I in starvation mode when I wake up every morning? What is the resting metabolic rate? Will it be in the final exam? Even Wikipedia seems to be a little confused in finding the difference between starvation mode and starvation response. Is starvation mode only for humans and starvation response for every other animal? Ok, I’ll stop being flippant now. In any case, Wikipedia provides the following two definitions:
Starvation response in animals is a set of adaptive biochemical and physiological changes that reduce metabolism in response to a lack of food.
Starvation mode is a state in which the body responds to prolonged periods of low energy intake. During short periods of energy abstinence, the human body burns primarily free fatty acids from body fat stores, along with small amounts of muscle tissue to provide required glucose for the brain. After prolonged periods of starvation the body has depleted its body fat and begins to burn primarily lean tissue and muscle as a fuel source.
So it seems that Wikipedia’s definitions are consistent with one another, and they make sense: Your body adapts to being subjected to long periods of time without eating, or eating low amounts of food, and those adaptations involve using lean tissue and muscle as fuel sources due to the depletion of body fat. Going further, chances are that someone wrote starvation mode instead of starvation response due to the former being more popular in use than the latter.
So, are we done here? Have we solved the great starvation mode mystery? No, not quite. In future posts we will go over the papers that Wikipedia itself uses as references. That way we might check Wikipedia’s accuracy, and we may be able to point someone else in the right direction if they’re wondering what starvation mode actually is, rather than they be mistaken or taken advantage of.
The papers that we’ll have a glance over are the following:
- Wang, Tobias; Hung, Carrie; Randall, David (2006). “The Comparative Physiology of Food Deprivation: From Feast to Famine”. Annual Review of Physiology. 68 (1): 223–251.
- Dulloo, Abdul G; Jacquet, Jean (2001). “An adipose-specific control of thermogenesis in body weight regulation”. International Journal of Obesity. 25: S22–S29.
- Dulloo, Abdul G; Jacquet, Jean (1998). “Adaptive reduction in basal metabolic rate in response to food deprivation in humans: a role for feedback signals from fat stores”. The American Journal of Clinical Nutrition. 68(3): 599–606.
- MacDonald IA, Webber J (March 1995). “Feeding, fasting and starvation: factors affecting fuel utilization”. Proc Nutr Soc. 54 (1): 267–74.
- Elia M (December 2000). “Hunger disease”. Clin Nutr. 19 (6): 379–86.
- Swaner, JC; Connor, WE (Aug 1975). “Hypercholesterolemia of total starvation: its mechanism via tissue mobilization of cholesterol”. The American Journal of Physiology. 229 (2): 365–9.
- Weyer, Christian; Walford, Roy L; Harper, Inge T S; Milner, Mike A; MacCallum, Taber; Tataranni, P Antonio; Ravussin, Eric (2000). “Energy metabolism after 2 y of energy restriction: the Biosphere 2 experiment”. American Journal of Clinical Nutrition. 72 (4): 946–953.
- McCue, MD (2010) Starvation physiology: reviewing the different strategies animals use to survive a common challenge, Comp Biochem Physiol, 156, 1-18.
If you are interested in getting a copy of them, I would suggest visiting your nearest public library, college or university library, or to look for the scientific hub that is closest to you.
See you next week. If you liked this post and would like to see similar material, please visit the Rebuttals to Fatlogic section of the blog.