How bad is it eating under 1200 calories a day?

I think you really should talk to a qualified nutritionist and doctor.
People asking such questions should really know better. Sorry but it's also borderline against forum rules too.

You MUST eat at least 1200 calories a day. If you eat 1199 you will instantly go into starvation mode and your body will start to break down your brain, heart, and lungs and store it as fat! Lol a little under is fine. It's best to discuss your diet and exercise plan with your doctor instead of relying on some arbitrary number the MFP staff pulled out of their @$$es. I'm on a medically supervised 800 calorie per day diet and if I logged exercise my net would be much lower. MFP totally overestimates calories burned through exercise. My doctor says my diet/exercise plan is fine and I value her opinion way more than what MFP has to say.

I think we missed the point. Is 50 - 100 calories a big deal? For me at ~2000 calories a day no. you at 1200, maybe.

Go here: http://www.myfitnesspal.com/topics/show/654536-in-place-of-a-road-map-2-0-revised-7-2-12

Read through it, run your stats through the tools int he links provided in that post. Find out what your BMR is (Basal Metabolic Rate) - the amount of calories docs would give you through a tube or IV to sustain your life if you were in a coma. Most people have a BMR above 1200 calories, which means if you're eating 1200 or less, you're barely giving your body what it needs if you stayed in bed all day. Most of us do get up, move around, go to work, do household chores, and exercise, meaning you need even more fuel to keep those functions going.

Yeah, a lot of people eat 1200 or less, say they feel fine, lost weight, etc. And most do at first - I did! MFP put me at the standard 1200 when I first signed up. After some initial weight loss, I stalled, saw no progress, was hungry, tired, had little energy to workout. Turns out my BMR is around 1400, so 1200 was way too low for me!

Now I'm eating around 1700 calories a day, usually more, and seeing fat come off of my body like I never did before. I'm not hungry or anxious about what I can eat that will fit in my goals for the day, and I have plenty of energy to get through my day and my workouts (weights/strength 3 days a week, run an avg of 4 miles 3 days, 1 rest day). I'm not a slimmer but still squishy version of my former self - I'm losing the fat, but keeping my lean body mass by fueling my body well, and I love it!

Check your numbers out through that link. You might be surprised at how much you've been short-changing your body. And eating more calories doesn't mean eating more junk food to meet the goal, or even stuffing yourself with healthy foods - eat small portions of more calorie dense foods like nuts and nut butters, avocados, healthy oils, full fat dairy.

Props!

Don't pay attention to the naysayers of 1200 cals. I net around 1200 on good days and I've been losing weight for months and have lots of energy. You don't look like you have much to lose, so if you're not hungry, then you're fine.

Starvation modes is for people with a super low body fat and people in 3rd world countries. You don't have to worry about this.

^- Don't listen to these people.. clearly they didn't do it for 4 years only to find themselves stalled and gaining in the end.

I did that for a long time, I'm afraid to eat food sometimes! I wasn't losing weight! I didnt understand why! I barely ate, and even with exercise not much was happening except being tired and crank and hungry all the time. Then I would binge and eat all kinds of crap and GAIN weight.

Yeah, "starvation mode" is a term that gets thrown around too much.. but LISTEN to the 1200 cal naysayers. I did it for 4 years and got no where.. I used the roadmap (that link you were given from the first real helpful person) and behold, my weight starts going down eating MORE. When I revert to eating around 1200 cals, my weight doesn't move again (so I have seen since using this site).

The 1200 calories is what MFP tells pretty much EVERYONE.. if it worked miracles and everyone did it we would all be incredibly thin. Don't accept a default setting.

Go read the road map, it is worth it! Ever since doing it I have seen weight come off after being stuck/gaining for years (yo-yo whoo hoo).. I was always tired (no energy, not eating enough) and always cranky. "Surprisingly" when you eat you're less obsessed with food (mentally) because you're not hungry and thinking about it, so you make better choices than running to the sugar.

These 1200 cal people will probably find themselves in the situation I was for a while in a year or two. It isn't as simple as eating 1200 cals or less a day.

1200 is good even less is better as long as the Food is High in nutrients. 100 calories of Broccoli provides you with 12 grams of protein, 0mg of cholesterol and 10,000 time Phytonutrients VS 100 calories of steak which is 2grams of protein and 45mg of Cholesterol. Just look at Gorillas and Giraffes they do not ever stop eating and they grow larger with muscle tone and are never obese. Plus eating less helps you live longer.

A slowed metabolism has nothing to do with ones ability to eat less!!!!! There is NO correlation between the speed of your metabolism and how much food you consume. There is however a correlation between a fast metabolism and the amout of calories you burn. Also a correlation between daily physical activity and daily dietary needs. How much food you stuff in your face depends solely on the choices you make, not your metabolism!!!

Also, 1200 calories is generic caloric intake for fat loss and should not be sustained 7 days a week for anyone unless they are sedentary.

Your main diet focus (for fat loss) should be:
1) A diet consistently of the proper macro and micro nutrients for your bodies needs.
2) A multi-vitamin
3) A low and high range of caloric intake (ex: eat close to 1200 calories 6 days/week and on the 7th day eat 1700 calories). Studies have shown the change from "starvation period" to the "cheat meal" and back to "starvation mode" will boost your metabolism.
4) Limit high-glycemic sugars (anything that spikes blood sugar)
5) Limit saturated fats, enriched foods, dried fruits, added sodium, etc.
6) focus on nutrient dense foods (whole grains, fatty acids, fibrous vegetables). The closer it is to its organic form the more filling it will be.

Sticking to the above will allow anyone to fill fueled on 800 calories or 4000 calories. Personally, I would always eat a minimum of 1200 calories unless you have doctors orders as its insanely difficult to get your macro and micro nutrients in under that amount. If you have issues still, I'd change up when ur meals are (heavier on carbs around workout, more smaller meals as opposed to few large ones). I also suggest protein with veggie at every meal even snacks.

And remember, the more active you are the more calories you can eat and still lose weight.

If you are lacking in eating fat you will also feel fatigued. It's better to be on a 1200 calorie diet and go over by a few hundred calories to have a serving of salmon or avocado to boost your energy levels.

Poor nutrition will hault your progress more than the amount of calories you consume anyway. And you want to be losing fat weight not muscle weight (which means ~1lb a week maximum) So be sure your nutrition is more important than caloric intake or you'll be a skinny fat person with clogged arteries, slow metabolism, a weak heart, and vitamin deficiencies!