Otf

OK, this is going to be a little complicated to answer completely but briefly.

I'm going to start with the TL;DR version, if you don't want more details: Yes, MFP intends you should eat those calories. That should keep your same intended weight loss rate. If you don't want to eat those calories on the same day, you can eat some of them on a later day(s). One way to do that is to look at weekly average net calories in the app, balancing that rather than balancing each individual day.

Longer explanation:

If your activity level in MFP is accurate, and you have a tracker synced to MFP, the two will communicate so that when the tracker sees you as having moved more than MFP expected, you get more calories to eat. It's important to recognize that those calories are all-day, all-ways calories, not just exercise calories. For example, if you have an active job or did energetic home chores, and your tracker sees that, your calorie goal in MFP may go up from that in addition to formal exercise.

Also, trackers aren't perfect, and it's important to have a feel that the added calories are reasonably plausible, or eating them all could make it difficult to meet weight management goals.

If you added the OTF calories to MFP by typing them in, that's different. You don't say. When you set yourself up in MFP, you set an "activity level". If you assumed your exercise into your activity level, then add exercise calories manually besides, that may be double counting. That would also compromise your weight management goals.

Here's a thing: 1000 calories is a lot of calories for one exercise session, like elite level fitness intensity if we're talking about an hour of activity, even for a fairly large person. I don't know what your fitness level or current height/weight are, nor how many OTF sessions you did, so maybe that's reasonable for exercise. For honesty, I don't do OTF, but I do machine row, and do strength train, so I kind of understand what's involved. Rowing is a good calorie burner, strength training isn't that great, but can be a bit more in those HIIT-style workouts.

I know it's a good workout, but the calorie numbers I've seen advertised by OTF sources sound iffy to me, especially at the top end. I believe they have you wear their trackers. Trackers in general are likely to over-estimate exercise calories for strength training, interval training (especially high intensity, but any interval pacing), possibly for newer exercisers, and for people who have a different maximum heart rate than the average as compared with the standard 220-age estimate for HRmax. (It's fairly common to be non-average). If you want an explanation of why they over-estimate, I can explain that, but I won't add to the length here unless you say you want to know. Those calorie estimates are also likely to be gross exercise calories (includes BMR/RMR), when what you want to add in MFP is net calories, ideally.

If you're getting a 1000 calorie adjustment from a tracker, and you're set at a low activity level in MFP, plus you have lots of other activity in your life from job, home, other hobbies, etc., the 1000 may be correct. If you're manually adding the calories, even if they came from the OTF fitness tracker, they may be over-stated.

In the case of a tracker you wear all day and sync to MFP, it's probably OK to eat most or all of the calories, at least until you've been calorie-counting daily for 4-6 weeks or a whole menstrual cycle. Once you have that much real-world calorie data and weight-change data, you can adjust your MFP calorie goal if necessary to fine-tune. If you added those calories manually, and didn't assume exercise when you set your MFP activity level, I'd be more inclined to eat only part of them, probably still a larger chunk, half or more, until the 4-6 weeks/1 cycle results are in. If you assumed exercise into your MFP activity level, it's harder to figure how much if any you should be able to eat back and still achieve your weight management goals.

Personal experience: I don't sync my tracker to MFP because reasons, so I add my exercise calories manually, after estimating them carefully. To start out here, I set my MFP activity level based on my life excluding intentional exercise, which was sedentary. After a month or so, I looked at results, and adjusted my calorie goal accordingly. I ate all of my exercise calories all through losing around 50 pounds in just under a year, and for 9+ years of maintaining my healthy weight since. It works fine. My weight changes were quite predictable, and still are.

If someone's trying to lose weight at a slow rate, and doesn't do very much exercise, like half an hour at 200-300 calories 3 times a week or something, it's probably fine for that person to skip eating those exercise calories, and let that speed up their weight loss a little.

OTOH, if someone is already going for an aggressive weight loss rate like 2 pounds/1 kilo per week, and does an actual few thousand calories of exercise per week, that's probably not a great plan. Fast weight loss increases health risks, can tank energy level, trigger more muscle loss than minimum alongside fat loss, cause things like hair thinning/loss, and make it hard to stay with that long enough to lose a meaningful total amount of weight.

In between those extremes, it's a judgement call about how much a person wants to risk their health, appearance, and so forth in order to speed up weight loss. For me, reasonable health and good athletic performance are key goals, so I eat my exercise calories. YMMV.

I hope that makes sense.

Best wishes!