We’ve had a few firsts recently.
- We have our first prolonged human study of the effects of Caloric Restriction, and
- Our first human study of early time-restricted-eating.
Calorie Restricted Eating Delays Aging in Humans
In a two-year, 218 participant study, researchers were able to show positive effects of caloric restriction (CR) on numerous clinical disease risk factors, including weight, tumor necrosis factor-α, and cardio-metabolic risk factors.
Unfortunately, I was unable to find out what the researchers considered as cardio-metabolic risk factors, so we’ll take a leap in guessing that they’re similar to metabolic syndrome risk-factors, which are the following:
- abdominal obesity,
- high blood pressure,
- high blood sugar,
- high triglycerides,
- low high-density lipoprotein (HDL) levels.
Participants following the CR protocol restricted their intake by 25%, while the control group ate as much as they wanted (ad libitum).
Participants saw the biggest improvements at the 2-year follow-up.
I have to note that there also seems to have been a greater decrease in T3 (active thyroid hormone) in the CR group, but nothing large enough to alarm researchers (1).
Okay, what does that mean?
Restricting your food intake 25% below ad libitum can help you lose weight (especially around your belly), lower blood pressure, blood sugar, and triglycerides, and boost HDL levels. It can also help you lower levels of tumor necrosis factor-α.
Looking to make this work for you?
Pick 3 days a week to eat less than you normally would. Be a little bit uncomfortable.
You might also consider following an eTRF schedule.
Early Time Restricted Feeding (eTRF)
Researchers studied 11 overweight individuals for 8 days.
- Days 1-4: Participants ate between 8am and 2pm (eTRF),
- Days 5-8: Participants ate between 8am and 8pm, eating the same number of calories as days 1-4.
- Researchers measured calorie burn, fat burn, and appetite.
At the end of the study, researchers found that the participants burned the same number of calories regardless of eating style.
Interestingly, they also found that hunger swings were reduced, night-time fat burn was improved, and metabolic flexibility (switching from carbohydrate to fat burn) was improved during eTRF (3).
This is promising news, and may lead to much-needed long duration studies in the future. Long duration eTRF studies on rodents have showed decreases in body fat and chronic disease risk.
Looking to feel less hungry, less hangry, and burn more fat?
Eat during a smaller window (8am-2pm or 10am-4pm, you get it), and consider skipping — or shrinking — dinner. You’ll end up fasting for about 18 hours, and making better use of that increased fat-burn.
Summing it Up
Eat during fewer hours throughout the day to burn more fat and decrease hunger swings. Maybe you’ll lose weight. Rodents do.
Eat about 25% less than normal and you’ll put yourself in a position to improve multiple markers of health.
Lastly, I’m not a doctor. This is not medical advice. I’m just a nerd who likes to read research, and I figured I’d be productive by sharing it with you.
I’m a nerd, I know.
I read it so you don’t have to.
ps. If there’s anything you’re curious about, and don’t have the time, patience, or know-how to learn about it, let me know. I’ll be sure to post on it if it’s worth-while, or I’ll answer you directly!
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J Gerontol A Biol Sci Med Sci. 2015 Sep;70(9):1097-104. doi: 10.1093/gerona/glv057. Epub 2015 Jul 17. “A 2-Year Randomized Controlled Trial of Human Caloric Restriction: Feasibility and Effects on Predictors of Health Span and Longevity.” Ravussin E1, Redman LM2, Rochon J3, Das SK4, Fontana L, Kraus WE5, Romashkan S6, Williamson DA2, Meydani SN4, Villareal DT7, Smith SR8, Stein RI7, Scott TM4, Stewart TM2, Saltzman E4, Klein S7, Bhapkar M5, Martin CK2, Gilhooly CH4, Holloszy JO7, Hadley EC6, Roberts SB4; CALERIE Study Group.
- The Gerontological Society of America. “In delaying aging, caloric restriction becomes powerful research tool in human studies.” ScienceDaily. ScienceDaily, 19 December 2017. <www.sciencedaily.com/releases/2017/12/171219215510.htm>.
- University of Alabama at Birmingham. “Time-restricted feeding study shows promise in helping people shed body fat.” ScienceDaily. ScienceDaily, 6 January 2017. <www.sciencedaily.com/releases/2017/01/170106113820.htm>.
- Image courtesy of: JÉSHOOTS.