What is the difference between being fat and obese?

Is being fat healthy? Some parents are very happy to have kids who are fat. They say fat is healthy, but being overweight isn't. Why would this be the case? What adverse health effects are there when one is obese (or fat, respectively).

  • 4
    That looks like there might be an interesting question underneath. However, in its current state it is almost incomprehensible. Please try to rephrase your question to make it clear what you want to know, what you researched and reasoned about your topic so far. Sep 18, 2017 at 11:41
  • Is it the same between obese and obese?
    – paparazzo
    Sep 19, 2017 at 15:01
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    I edited your question to try and clarify what I think was your intent. If I made it into something you did not intend, you can revert my edits. However, as originally worded it was unclear what you meant so if you revert, please also edit to clarify.
    – Carey Gregory
    Sep 19, 2017 at 15:48
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    @CareyGregory I still didn't really understand what was meant with the last paragraph. Do you think my new edit was in spirit of the OP? At OP: Please rollback my edit or edit the question yourself if I have misinterpreted you.
    – Narusan
    Sep 19, 2017 at 16:00
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    Thanks for your feedback, yes I mean what is the difference between fat and obesity? Then is healthy fat for the body? @Narusan-in-coma
    – Aldan
    Sep 20, 2017 at 1:35

1 Answer 1


Fat is a lay non medical term. Obesity is defined as a BMI > 30 in adults

What are overweight and obesity?

Overweight and obesity are defined as abnormal or excessive fat accumulation that may impair health.

Body mass index (BMI) is a simple index of weight-for-height that is commonly used to classify overweight and obesity in adults. It is defined as a person's weight in kilograms divided by the square of his height in meters (kg/m2).


For adults, WHO defines overweight and obesity as follows:

overweight is a BMI greater than or equal to 25; and obesity is a BMI greater than or equal to 30.


Health Risks

Are related to the degree of being obese.

It makes you more likely to have conditions including:

  1. Heart disease and stroke.
  2. High blood pressure.
  3. Diabetes.
  4. Some cancers. Increased rate of relapse from eg. breast cancer
  5. Gallbladder disease and gallstones.
  6. Osteoarthritis.
  7. Gout.
  8. Breathing problems, such as sleep apnea (when a person stops breathing for short episodes during sleep) and asthma.
  9. Psoriasis
  10. Poor response to drugs for arthritis


  • Question - Does the medical community still use the BMI charts as a reference, given their known flaws and origins?
    – JohnP
    Mar 12, 2018 at 14:26
  • @JohnP My PCP dutifully records my BMI at every physical, and my insurance company wants to know what that number is, so I'd say the answer is yes.
    – Carey Gregory
    Mar 12, 2018 at 14:43
  • @CareyGregory - Sad, but not surprising. Also not surprising your insurance wants it as It was invented by a math/statistician, and adopted originally by insurance companies.
    – JohnP
    Mar 12, 2018 at 14:56
  • Our patients aren't usually muscular athletes Mar 12, 2018 at 17:29
  • Nevertheless it's a badly flawed measurement and it's used blindly to make decisions. I have a very athletic friend who was denied life insurance based on his BMI. He had to pay for a hydrostatic body fat test to get the denial reversed.
    – Carey Gregory
    Mar 12, 2018 at 18:50

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