Redam Caloric restriction

Flashcard 1

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Front: What is the primary independent variable in the study?

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Back: Caloric Restriction (CR), specifically a 25% reduction in energy intake compared to an ad libitum control group1.

Flashcard 2

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Front: What were the main categories of dependent variables measured in the study?

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Back: The dependent variables included energy expenditure, body composition, hormonal mediators, and markers of oxidative stress1.

Flashcard 3

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Front: How was energy expenditure measured in this study?

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Back: Energy expenditure was measured using a metabolic chamber to determine 24-hour energy expenditure (24hEE), and sleep energy expenditure (SleepEE)2.

Flashcard 4

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Front: What is metabolic adaptation, as seen in the study?

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Back: Metabolic adaptation refers to a reduction in energy expenditure greater than what would be expected from the loss of tissue mass2. In this study, SleepEE was reduced in the CR group by approximately 7% compared to the control, after accounting for changes in body composition2.

Flashcard 5

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Front: What changes were seen in the hormonal mediators in the CR group?

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Back: The CR group had reductions in leptin and thyroid hormones (T3 and T4), and an increase in adiponectin3.

Flashcard 6

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Front: What markers of oxidative stress were measured in this study?

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Back: The study measured urinary F2-isoprostane excretion (specifically 2,3-dinor-iPF(2α)-III and three additional isomers) and serum protein carbonyl concentrations1.

Flashcard 7

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Front: What was the key finding regarding oxidative stress in the CR group?

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Back: The CR group experienced a significant reduction in oxidative damage, as indicated by decreased levels of urinary F2-isoprostane excretion2.

Flashcard 8

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Front: How did caloric restriction affect 24hEE?

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Back: Both the CR and control groups saw reductions from baseline in 24hEE. However, after accounting for changes in body composition, 24hEE was not significantly different from the control group2.

Flashcard 9

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Front: How did caloric restriction affect SleepEE?

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Back: The CR group experienced a reduction in SleepEE from baseline and a 7% reduction compared to the control group after accounting for changes in body composition2. This is an indication of metabolic adaptation2.

Flashcard 10

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Front: What are the two primary theories of aging supported by this study?

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Back: The study's findings support the "rate of living" theory of aging and the "oxidative damage" theory of aging1.

Flashcard 11

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Front: What was the study's overall conclusion?

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Back: The study concluded that sustained calorie restriction in healthy, non-obese humans can lead to metabolic adaptation, reduced oxidative stress, and improvements in biomarkers of aging, thus supporting both the rate of living and oxidative damage theories of aging3.

Flashcard 12

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Front: How many participants completed the study?

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Back: 53 participants completed the study (34 in the CR group and 19 in the control group)4.

Flashcard 13

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Front: What were some of the study's limitations?

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Back: The study's limitations include a relatively short duration of 2 years and a lack of prescribed diet composition beyond calorie reduction3.

Flashcard 14

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Front: How did the study address the impact of weight loss on energy expenditure?

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Back: The study accounted for the loss of fat mass and fat-free mass when calculating energy expenditure to isolate the impact of metabolic adaptations from weight loss alone2.

Flashcard 15

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Front: What are some potential future directions for this research?

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Back: Future studies should explore dietary composition (e.g., antioxidant-rich foods) and possible CR mimetics like resveratrol3.