Anorexia/Eating Disorders/Overweight vs Underweight


Hi I'm 17 5'6" 104lbs I've always been skinny and my friends all tell me I'm too skinny. But right now I'm so confused, the other day our health class was talking about body weight and fitness I always thought I was fit and strong for my size.  Our teacher suggested in short terms that being a little over weight is better than being under weight ? I didn't believe her and told my friends that this can't be right, so I few days later my friends thought it would be a good idea to do an experiment at out gym room if I agreed. There is another girl
In our class who is my age and same height only she weighs 203lbs very over weight she agreed to do the experiment to see who had the best endurance and strength over varies tests. The first being strength with dumbbell 5lbs bicep curls I managed 15 reps till my wrists got to weak. Nikki on the other hand done 39reps
I couldn't believe my eyes I new then this wasn't going to be easy. Next was thigh strength just a plain old thigh master starting with as many sets of 10 reps we could do I managed 3 sets of 10 the last half I really really struggled with. But again Nikki did 7 sets of 10 reps ??? How she was just smoking me. Next was a bit of cardio rowing machine the resistance was set to 2 and the first to 500m was the winner neither Nikki or myself workout so this was all fair I guess . Nikki got me again by about 20 seconds what ?? How is this happening I was exhausted she still looked sooo strong? The  Last was a full on last one standing treadmill test.
Incline 6 speed brisk walking I thought I would win this hands down she would be to fat to last the distance
We'll guess what? down I went yep I tried to push it as hard as I could for as long as I could I didn't want her to win this one,Nikki the over weight girl has beaten skinny me all morning long at everything, I lasted till around 30 min on the treadmill before I got dizzy and sooo weak in my knees I almost fell Nikki still going strong sweating and puffing a bit but still walking. here I was sitting down so weak and exhausted watching her in disbelief she went at least another 20 min before quitting
My question is how come she is sooo much stronger in her arms wrist and thighs than me it looks all fat ?
And how can she have twice the cardio endurance than I do?.

Hi Susie,

Your teacher is right. The more you weigh, the stronger you are. You have more body mass to move the weight. Now if you weighed the same and one of you had more muscle, it would make a difference. But given your differences in weight, her extra weight/strength will be to her advantage. The other factor may be your diet (especially for the cardio). You need calories to exercise. Assuming she eats more than you do, she has more energy (calories) than you do.

Make sense?

Anorexia/Eating Disorders

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Mary Pritchard


I can answer questions about the psychology of eating, disordered eating attitudes and behaviors such as drive for thinness, drive for muscularity, binge eating, body dysmorphia, dieting, excessive/obsessive exercise, and body dissatisfaction. I can also answer questions about anorexia and bulimia.


I have a PhD in Psychology and teach courses in the Psychology of Health and the Psychology of Eating. I have been conducting research on disordered eating and exercise behaviors for 15 years.

Midwestern psychological association, rocky mountain psychological association

Over 50 peer-reviewed journal articles in journals such as Eating Behaviors, Eating Disorders, and Eating and Weight Disorders

PhD in Psychology from the University of Denver

Awards and Honors
30 teaching awards, have received funding to conduct my research from academic institutions and state and local government

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