Anyone can be overweight doing anything, if you eat enough ;) I used to be overweight biking 130 miles a week on average. Would see other heavy cyclists. 

Cycling is great for joints though, doesnt really hurt ya. So long as you dont flare your knees out while you ride

I think there are two major factors in play:

1. You are actually filling your glycogen reserves which adds "water weight."  This is actually the same phenomenon, in reverse, when you start a new diet.  Rather than losing water weight the first week or two due to a carbohydrate/energy deficit you are gaining water weight because of your carbohydrate consumption.  Rather than driving the car with 1/4 tank you're keeping it full.  It's unlikely you've gained 2 pounds of actual fat each week.
2. When you first started training you "hit the wall" due to an empty tank (#1) but now you're over-estimating your energy/carbohydrate needs.  Carbohydrates are absolutely essential for endurance sports but it's also very easy to overfeed and overindulge.  Exercise inherently makes you hungry and there can also be a psychological effect of entitlement of justification because you "just ran 20 miles."  I struggle with the same thing as a cyclist.  Try dialing it back a little bit with the gels and mid-run snacks and find the middle ground to stay fueled just enough.

And as always, make sure you are really eating what you think you're eating.  Also you should be eating real food and not just supplements.  You're putting stress on your body that needs to be repaired and you should nouri****

Thank you! I appreciate it!

Hello  I am about 9-10 months RNY Post op-   In the first 7 months I lost 155lbs, from 337 down to 172. I have started training for a half marathon in mid October and a possible Marathon the first week of November.  (I am 50 years old) Since I have started running and especially running long distances I am hungry all of the time. I have worked up from walking 12 miles to jogging 17.25 this past weekend. I am really not a runner, I can only jog. I cannot do an 8 or 10 minute mile, I am very slow at 13-14 minute miles. Most of you guys probably walk faster then I jog :) . I am trying to build up endurance for 26 miles and it will take me about 6 1/2 hours to complete the marathon about 3.5 hours to complete the half marathon. When I jog the long distances once a week on Saturday I take the energy gels one per hour and it is 100 calories and 22 carbs. This past Saturday I took 4 gels and it took about 4 hours to jog 17 miles. When I jog like this I am hungry all of the time. I am very worried about stretching my patch out. I continue to eat protein supplements, Isopure, Pure Protein Bars, and Quest bars.  I have added a lot fruit grapes, bananas, and strawberries. Unfortunately I eat a lot of food at night. I am jogging 40-45 miles per week.  In the past month I have gone from 172 up to 180. I have a lot of feelings about the weight gain, frustration with myself, panic, guilt, and saddened thinking I am going to gain so much weight back. In other forums and my close family have told me maybe I should just quit jogging and not train for a marathon so that I do not gain weight. I guess I have made a commitment to myself and want to continue on. When I was 30 I ran the half marathon twice, but have never made it for 26 miles. I would like to go to a support group at my program, but they are only on Monday nights at 5:30 and it is a 3 hour round trip and I work full time. There is another program close to me but they only meet twice per month and I am having trouble getting to the meetings because they are during the day and I am at work.  When I started jogging longer distances and just had probably less then 100 carbs per day with no fruit I actually felt week and had to sit down many times. I feel like I need the carbs to keep up my energy.  This morning I jogged 7.5 miles, I have had 1800 calories, 130 grams of protein and 118 grams of carbs , 32 grams of fiber, and 38 grams of Fat, I have not had any regular food, just protein bars and isopure.  Anyway I have gained 2lbs a week for the past month and I am up to 180.  When I had my last office visit about a month ago they told me I should keep my weight range between 172 and 178 and not go above and here I am at 180.00 . I struggle with hunger and craving food all of the time. I am looking for suggestions? constructive criticism and good advice about what to do.  I hope it is okay if I cross post this in the RNY forum. I am really worried about regaining all of my weight. I do not understand how I can gain 8lbs while jogging 40-45 miles per week. Any advice or words of wisdom would be greatly appreciated. So thankful for everyone here .- thank you! 

http://www.vox.com/2016/4/28/11518804/weight-loss-exercise-m yth-burn-calories

Check out the above article.  I found it helpful in putting exercise in it's proper for me place.  For me it's important that I move and keep myself able to do the things I want to in life.  I want to be able to walk quickly a 5k anytime I please.  I want to be able to walk quickly a 10k with a couple weeks planning.  I want to walk quickly a 1/2 marathon in December this year.  I do not want to job a 5,10, or 1/2 this year due to my feelings that it's not necessary but also that I've put enough strain on my joints for awhile being obese.  

When I got done with my 6 weeks post op I joined a fitness group.  The first thing the instructor said... I do not believe in exercise to loose weight.  We will work out, we will sweat, and we will get more fit.  I took that home and digested it, and remembered that your right a lot of people on here seem against exercise.  However once reading the info above and looking at what those against exercise was really saying, I came to a few conclusions.

Not exercising is not the primary reason I got fat.  I was eating 1/2 a pizza while watching tv, I drank sodas all day, I visited Starbucks and McDonalds the same day, I ate a lot of processed high sugar and high fat foods.  I did this for years and years until I called a halt to it.  No amount of exercise was going to cover up those horrible habits.  I can drink a large frappe in 15mins but there is not one exercise on earth that I can think of that will burn off that many calories in the same time.  So to me food is my first concern, exercise is there to help me feel better, tone muscles, and help me do my daily grind. However I'm not going to count on it to loose weight.