from Hacker News

Timeframe of 8-hour restricted eating irrelevant to weight loss

by hilux on 3/14/25, 5:24 PM with 87 comments

  • by bhaney on 3/14/25, 7:58 PM

    As other people are mentioning, I think the key factor for weight loss in any of these diets (intermittent fasting, keto, etc) is just making it more difficult to consume calories, which leads to a caloric deficit.

    I have a somewhat odd diet, where I naturally prefer to eat a single large (~2000 kcal) meal each day, and don't really eat outside that. I've been maintaining pretty much the exact same weight to within 5lb for years like this, despite it effectively being an extreme ~30-minute time-restricted-eating window.

  • by gwerbret on 3/14/25, 5:45 PM

    The title in HN ("(Any) 8-hour time-restricted-eating window effective for weight loss") is heavily editorialized from that of the NIH blurb ("Timeframe of 8-hour restricted eating irrelevant to weight loss"), but actually better reflects the findings of the actual paper ([1], unfortunately paywalled). They found that people who fasted for 16 straight hours a day lost (a little bit) more weight over 12 weeks than those who followed a Mediterranean diet. However, the weight loss didn't represent a loss of visceral fat (around the abdominal organs, fat which is more likely to be associated with diabetes and cardiovascular disease) and so the essential finding was that the time-restricted fasting made no difference.

    1: https://pubmed.ncbi.nlm.nih.gov/39775037/

  • by paulpauper on 3/14/25, 7:01 PM

    "Effective" as in "not very"

    The concept of 'eating windows' or timed eating has been studied and tested forever. the difference, if any, is basically nothing. It comes down to eating less. This is why GLP-1 drugs work so well when nothing else does at preventing people from putting as much food in their mouths.

  • by hodder on 3/14/25, 7:06 PM

    It is important to understand that time restricted eating is behavioral adaptation to reduce caloric consumption. A calorie deficit is what drives weight loss.

    Here is a list of similar things that also "work". It is key to understand that "working"- meaning weight loss is the result of a deficit of energy requiring the body to use stored fuel (fat) as energy over time:

    -higher protein is more satiating

    -higher fiber is more satiating

    -keto diets are for most people pretty satiating so they reduce caloric intake

    -GLP1s like Ozempic and Mounjaro lead you to feel "full" and eat less through a few mechanisms - slowing digestion, stabilizing insulin and blood sugar

    -Drinking lots of water

    -subbing out sugars with artificial sweeteners

    -fasting, intermittent fasting, time restricted eating, alternate day fasting. For some can lead to a binge but if you adhere to it you are likely to consume less calories

    -switching from processed foods to whole foods high in fiber and protein is more satiating

    -wearing tighter and more revealing clothing will lead one to eat less

    -weighing yourself daily will lead you to eat less (assuming you understand thermodynamics)

    -exercising and cardio will lead you to burn more calories. Muscle mass accrued over time burns modestly more calories than fat mass and cardio burns calories directly

    -counting calories directly (leads to greater adherence). Just like budgeting. If you don't measure and estimate what is going in vs going out at all and have no experience measuring you are unlikely to succeed.

    It is important to understand that NONE of the above are a substitute for a caloric deficit for losing weight but rather one possible path to CAUSING a caloric deficit. The deficit is still required. These are behavioral tools. Hormones, PCOS, insulin etc are also not workarounds to the laws of thermodynamics. They can make you more hungry or burn more or less calories at the margins but they dont change the equation of calories in vs calories out.

    Often people confuse the behavioral method to achieve weight loss with the mechanism driving it, and this leads to most of the confusion on weight loss outside of scientific literature (among blogger quacks, fitness guru snakeoil salesman etc.)

    Rant over.

  • by rich_sasha on 3/14/25, 7:43 PM

    I have only ever gained weight with intermediate fasting. When my window opens, I feel so hungry that I keep eating.

    I know supposedly you adapt to it and don't feel that extra hunger eventually, but somehow not me.

  • by nsxwolf on 3/14/25, 7:34 PM

    So just skip breakfast?
  • by beardyw on 3/14/25, 7:17 PM

    I mostly have breakfast at about 7am. So no more food after 3pm? Sounds hard to sustain in a normal kind of life.
  • by deadbabe on 3/14/25, 6:34 PM

    If you find yourself thinking about food all the time, that’s not healthy or normal. If you finish meals and are still hungry, that’s not normal.

    Normal people think about food only when they’re hungry, then they eat, and don’t think about it again until their next meal. It’s very easy to go 8 hours without eating this way.

  • by moltar on 3/15/25, 12:11 PM

    I don’t eat all night, which is more than 8 hours. Doesn’t seem to work.
  • by parliament32 on 3/14/25, 8:55 PM

    Turns out the key to weight loss is just "eat less" (calories, not volume).

    If you need a schedule and restricted hours to do that, great. If you need to track your calorie numbers (or some abstraction-of, like Weight Watchers points), great. If you need to "trick" yourself by eating high-volume-low-calorie foods, great. Whatever works for you. Just, less.

  • by rabid_turtle on 3/14/25, 5:46 PM

    bREAKfAsT Is THE MOST IMpoRTaNT meAL Of THE daY!