What I Learned Series 5: Calorie Restriction and Health: Part 1

What I Learned Series 5: Calorie Restriction and Health: Part 1

The set of lectures on calorie restriction and health were such an eye opener and there was so much information so as always with these series, I will keep them as concise and possible!

Calorie restriction can decrease the biological rate of aging and increases both average and maximal lifespan. Caloric restriction has also been shown to retard chronic diseases such as cancer, vascular diseases, diabetes, autoimmune diseases, and neurodegenerative diseases.

HUMAN RESEARCH of Calorie Restriction

The following studies have played a major role in the discussion of calorie restriction:

  • Okinawa Study
  • Bioshpere 2
  • Calorie Restriction Society

1. Okinawa Study

losing weight

Energy intake by school children <62%, energy intake of adults was <20% less than that of the Japanese national average, and <40% of the average American.

More recent data suggested a 10-15% energy deficit.

*There was a natural laborious occupation and daily activities as farmers and diet was rich in vegetables 


Mortality: The rates of death of Okinawans between the age of 60 and 64 years was 50% lower than that of Americans. 

Cardiovascular diseases and cancer: In Okinawa were only 60% compared to the rest of Japan.

Okinawans who move to the mainland have mortality rates higher than those who remain on the island. Traditional Japanese cuisine, or washoku, is very healthy (the only thing you should watch out for really is the high salt content in some dishes). It uses lots of vegetables, seaweed, legumes and so on, with a relatively small amount of protein from fish or meat.

2. Biosphere 2

Bioshpere 2 was a very interesting study where 8 participants chose to live the rest of their lives in a bioshpere where the environment was controlled their diet was from their agricultural system wherein food had to be planted and grown without chemicals. Bioshpere 2 ended after 2 years due a oxygen levels decreasing and a possible fault in the system.


It has been suggested diets were restricted by ~750 kcal/day.

BMI Males <19% (19.3 ± 0.9 kg/m), BMI Females <13% (18.5 ± 1.2 kg/m). In addition to reductions in BMI subjects were found to have marked reductions in:

  1. Blood pressure
  2. Fasting blood glucose
  3. Insulin
  4. Cholesterol
  5. T3
  6. White blood cells

3. CALERIE Study (Comprehensive Assessment of Long-Term Effects of Reducing Calorie Intake)

The CALERIE Study was a multi centre study in USA, which was a randomized, controlled trial investigating the effects of 25% CR:


3 groups of subjects:

1.12 months of 25% CR in 24-45 year old healthy overweight men and women

2.6 months of 25% CR n in overweight men and women aged 25 – 50

3.12 months of 20% CR in 50-60 year old healthy overweight men and women.

What I Learned Series 5: Calorie Restriction and Health:  Part 1

Redman LM & Ravussin E (2011)


6 months calorie restriction led to a significant decrease of:

  1. Body weight (~10%)
  2. Body temperature
  3. Energy expenditure (RMR)
  4. Body fat mass, visceral and subcutaneous adiposity.
  5. Fasting insulin and glucose

12 months calorie restriction led to decrease:

  1. 10.7% of body weight.
  2. BMI from 27.2 ± 0.6 to 24.4 ± 0.6
  3. Visceral and subcutaneous adiposity
  4. Circulating leptin
  5. Fasting insulin and glucose
  6. Improved insulin sensitivity

What I Learned Series 5: Calorie Restriction and Health:  Part 1

4. Calorie Restriction Society

how to gain weight

Most studies on calorie restriction are focused on people who need to lose weight (above the average BMI) but the Calorie Restriction Society focused on those with a healthy BMI as baseline to see what calorie restriction does to the body.

  • Members of the society (18 subjects) aged 53.2 ± 10 [BMI 19.6 ± 1.9] were compared with age matched subjects [51.4 ± 12] on a standard diet [BMI 25.9 ± 3.2].
Check out:  What I Learned Series! 3: Differences Between a Dietitian and a Nutritionist

What I Learned Series 5: Calorie Restriction and Health:  Part 1

What I Learned Series 5: Calorie Restriction and Health:  Part 1

Holloszy JO & Fontana L (2007)


  • Clearly the CR group were in better health than those on standard diet
  • Also risk factors for future cardiovascular and metabolic disease were very low.
  • Good evidence of the value of calorie restriction for health.
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Jonathan Sumner

Who am I? Trainee Diet Police? Nope!

I want to improve peoples’ relationship with food; To fall in love with meal times rather than them focusing on numbers - For people to be healthy, be comfortable in their own skin, and to love themselves. 🙂
Jonathan Sumner
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