Although people may never agree on the ideal thigh size for women and men, most experts agree that 40 inch thighs are much bigger than normal.
To put things into perspective, most people don't have a 40 inch waist or 40 inch hips, so to have 40 inch legs means that your thighs are very large indeed.
With that said, this article explores the reasons why people have 40, 42, and even 45 inch thighs.
Along the way, we'll also explain how you can safely slim your thighs so that they don't rub together when you walk (or make buying pants that fit a nightmare!).
Are 40 inch thighs too big?
In most cases, yes, 40 inch thighs are too big. Let's look at some real-life scenarios to learn precisely why 40 or even 44 inch thighs are overly large.
First off, if you have 40 inch legs, then it's highly likely that you're obese, which is when your BMI is over 30 (you're classed as overweight if your BMI is over 25). 
So, presuming that your 40 or 44 inch thighs are indicative of you being obese, your current size comes with numerous health risks such as diabetes, cardiovascular disease, and sleep apnea.
According to US research, having a high BMI also reduces your life expectancy by around 5-10 years. 
On a practical level, having 40 inch or 46 inch thighs, for example, can lead to skin chafing, which can make everyday activities like walking around the store very uncomfortable.
Similarly, it's very difficult to buy clothes that fit you well when your thighs are, let's say, 41 inches.
A lot of people don't have the money for tailored clothing, and so you often end up wearing either skin-tight pants that are baggy around the waist or pants that fit your legs but which are loose around your midsection.
How do you get 40 inch thighs?
While there are some professional strength athletes (professional bodybuilders, elite-level powerlifters, strongmen), who might have 40 inch quads, most people who have 40 inch thighs have them due to obesity.
The body accumulates fat faster and in much greater quantities than it puts on muscle mass.
Add in the widespread availability of junk food and a chronic lack of exercise, and you can see why some people pile on the pounds at an alarming rate.
The good news is that you can drastically reduce the size of your thighs—and your other body parts—by eating in a calorie deficit. This entails eating fewer calories than your body needs to maintain its current weight.
Besides helping you to expend energy and thus shed fat, cardiovascular exercise can prevent the onset of cardiovascular disease and diabetes. 
Regular exercise also improves your insulin sensitivity,  which helps your body to use blood glucose more effectively. It also reduces your inflammation, which can help you to recover from your workouts quicker.
Does anyone have 42 inch thighs? How about 44 inch thighs?
While there are examples of people with legs that are 42 inches long, there are few cases of people with 42 or 43 inch thighs in circumference.
There is, however, an interesting story about NFL player Robert Newhouse, who is reported to have had 44 inch thighs. 
Football players often have comparable physiques and levels of muscle mass to powerlifters and strongmen, so it's conceivable that a hard training, well-built football player like Newhouse could have had 44 inch thighs at his peak.
Who has 49 inch thighs and 50 inch thighs?
One thing's for sure; even the biggest strength athletes don't have 50 inch thighs.
The only people who do, as you might have guessed, are those who are obese or who have unfortunate medical conditions such as lipoedema.
49 inch thighs, for example, are more than double the average size, a measurement that you certainly couldn't attain through squats alone.
Although there is no ideal when it comes to the size and shape of your thighs, there comes the point when the size of your legs could be telling you something serious.
If you have 40 inch thighs, then that's a sign that you're likely obese, and perhaps severely so.
On the positive side, there are many inspiring examples of men and women who have successfully slimmed their 40" thighs and lost incredible amounts of weight. So just because you're overweight today doesn't mean that you still have to be overweight a year down the line.
As always, sustainability is key. It's much better to follow a simple exercise regime that you can stick to and lose 1-2 pounds per week than it is to lose 5 lbs in your first week and then pile it back on after.
- Obesity. (2020, February 21). World Health Organization. https://www.who.int/health-topics/obesity/
- Fruh, S. M. (2017). Obesity. Journal of the American Association of Nurse Practitioners, 29(S1), S3–S14. https://doi.org/10.1002/2327-6924.12510
- Pinckard, K., Baskin, K. K., & Stanford, K. I. (2019). Effects of Exercise to Improve Cardiovascular Health. Frontiers in Cardiovascular Medicine, 6. https://doi.org/10.3389/fcvm.2019.00069
- Conn, V. S., Koopman, R. J., Ruppar, T. M., Phillips, L. J., Mehr, D. R., & Hafdahl, A. R. (2014). Insulin Sensitivity Following Exercise Interventions. Journal of Primary Care & Community Health, 5(3), 211–222. https://doi.org/10.1177/2150131913520328
- Sullivan, J. (2018, June 9). STAR: On and Off Field, Robert Newhouse Truly Loved By All. Dallas Cowboys. https://www.dallascowboys.com/news/star-on-and-off-field-robert-newhouse-truly-loved-by-all-351201