A few weeks ago I read an article in my email which states that 50 percent of Americans are obese which is usually defined as having a BMI of greater than 30 kg/m². BMI relates weight to height. Americans are clearly obsessed with being thin and body shape. I hear complaints and worries about weight many times each day in the office due to this underlying obsession and also because so many of the medications we use have a tendency to promote weight gain and thus raise the topic. I am also motivated to write this series of blogs by the difficulty of loosing weight and keeping it off for a prolonged period. Before proceeding I should make clear that gaining weight and loosing weight involves different factors for each person but semi-starvation diets are universally experienced by our bodies as a famine state. One process does not fit all for either loosing or gaining weight. The problem is complex and I am sure it involves dozens of processes many of which remain unknown at this juncture. There is no doubt these are world class problems and even partial solutions would merit a Nobel prize.
I thought I would start off by reviewing an old classic book, The Biology of Human Starvation by Ancej Keys published in 1950. In the book he discussed the physical, mental, and social reactions of 32 conscientious objectors, college-educated, men who thought they were participating in a starvation project as a preparation for going overseas after WWII to help famine victims. The study itself took place over a year with the first three months as a control period, the second six months were a period of semi-starvation, and the final three months were a re-feeding period. The men were tested all through this period.
During the second six months of semi-starvation the men were required to lose 19 to 28 percent of their body weight and were fed an average of 1,570 calories with carbohydrates adjusted up or down for each individual depending on their weight loss.
They participated in daily physical activity including 22 miles of walking, 30 minutes on the treadmill, and 15 hours of clerical or maintenance work as well as walking to the dining room. These tasks, which continued for the entire year, were done poorly during the final two months of the semi-starvation period.
What were the physical changes noted during the fast weight loss efforts in this study?
- Weight decreased by 18.8 to 29.3 percent
- Size decreased in thigh, upper arm, upper trunk,waist breath and neck size.
- Heart volume decreased about 20 percent
- Work output of heart per minute was reduced by 50 percent
- Pulse rate declined from an average of 56 to 38 beats per minute.
- Basal metabolic rate was decreased by the end of the 6 months of semi-starvation by 40 percent. This was converted into caloric savings of 600 per day.
- Edema was noted and measured in semi-starvation phase as an increase in ankle circumference.
- Subjects complained of cold hands and feet even on hot days.
- Subjects complained of feeling weak and tired.
- Work capacity declined including lifting, walking, pushing and standing.
- Decrease in arm and leg strength as well as endurance.
- Complaints of muscle soreness and muscle cramps.
- Increased frequency of urination.
- Sexual function and testes size were reduced.
- Skin became dry, scaly, inelastic and hair became thin, dry, and fell out.
- Teeth and bones were not adversely affected.
- Special senses were unaffected except that hearing acuteness improved substantially, i.e. ordinary sounds were experienced as too loud and irritating.
The above summarizes the part of this study showing the extensive changes in a number of bodily functions that result from a semi-starvation regimen lasting six months. The men took in about 50 percent of the calories consumed in the three month control period. In the next blog I will summarize the effects on personality.