Ate pizza today...

I have to say you didn't eat the whole pizza while sitting on the couch doing nothing, you're up and moving, you've burned calories. You don't want to do it everyday but on occasion even once a week isn't bad at all. You're staying within you're calories and doing good. Don't feel bad...be thankful you're changing. Keep at it and do your best.

Feeling guilty over breaking a dietary rule often sets up a cycle of restriction/binge. Allow yourself some flexibility and if you are worried about what you will eat in the future, plan out tomorrow's menu today and make sure you carry food with you so you don't make poor choices while doing errands or something. But, you were within your cals so really you should feel great that you didn't let a lapse in food choices turn into a full-blown binge. This actually means you are further along than many of us, so feel pleased, not guilty!

It's all good, the fact that your making a conscious effort to watch what you eat is a great start. Even if you gone over your calorie count for the day it would of been fine. Tomorrow you start fresh and have a nice healthy day. I had pizza today but I knew I would exercise on a day a norm don't to kind of offset it the yummy but not so good food

Pizza is awesome, enjoy.

I'm more concerned about the goal you mentioned on your profile of wanting to lose 20 lbs in 5 weeks. If you approach this like a crash diet you will not be able to sustain it. Just try to eat a balanced variety of foods, exercise and stay within your calorie goals and you'll get there. Slow and steady...

I ate pizza today.
It was delicious
I've lost 40 pounds so far
it's fine

So I just started dieting 4 days ago and today I ate pizza

Yummy!

I feel terrible about it

Why? It's food. You didn't donkeypunch a nun, you ate pizza. Get a grip.

, I didn't exactly go over my calories today and I exercised as well

Then congrats! You will lose weight if you continue this.

but it feels as though I'm cheating already.

Eating pizza and hitting your nutritional targets is not cheating. It's called winning. Congrats on being a baller.

When do you guys feel guilty about what you ate?

Never.

But hypothetically let's say I went into a senior home and they were serving tacos, and Leonard was sitting next to his oxygen tank, about to take a bite of his taco, and I slapped him in the back of the head, knocking the taco into the air, whence I catch said taco and take a bite.....

I'd feel guilty.

Other than that, no.

This. As as a species, we need guilt to stop us from killing and thieving all the time, not to help us avoid yummy food.

When I was losing I ate 3/4 of a pizza at a time, now I have a whole one, but I never felt guilt.

Too bad guilt isn't working too well for that.

The only food guilt that is useful is if it somehow motivates you to do a fitness activity. Otherwise drop it and have the pizza.

I think the key here is that you're on day 4, so it's not surprising that you feel bad. It can take a while to get into the swing of this and to learn to let go of those guilty feelings. When you've been doing this for a while, well you'll either decide to cut things like pizza out of your diet altogether (works for some people I guess) or you'll realise that if it fits into your goals, then it's fine. There's nothing to feel guilty about.

When I say "fits into your goals", it may be that you only want to focus on calories, it may be that you want to focus on overall nutrition, in which case you'll want to keep an eye on your macronutrient (protein, fat, carb) targets too. You can still eat pizza and have an overall balanced, nutritious diet though.

Try and separate feelings of guilt and shame and "doing it wrong" from eating. It's just food. Have too much of it, and you'll gain weight obviously, but from my own experience and from looking at others around me, feeling guilty about eating just causes more problems. If you find that eating pizza doesn't fill you up enough for the amount of calories, then you might want to make it an occasional thing, but that's something you can figure out along the way.

As for your friends' criticism, don't listen to them. This is your life, and your weight loss. You have to find what works for you. It's true that nutritional balance is important for health, but purely for losing weight/fat, calories in/out is the most important thing. Once you've been at this a while, and have seen results, you'll feel stronger a bout it and hopefully they will back off a bit. Personally I started off on MFP paying attention only to the calories, and it worked for me. As time went on, I couldn't help but start paying attention to my diet in general and improving it. That doesn't have to happen overnight though. Make changes that you can sustain permanently, and you'll have success.

No food should make anyone feel guilty!! It's all about healthy eating, not minimal eating. I love to splurge now and then on something really decadent, and if it means I go over my calorie goals for one meal or one day, then so be it. I make sure I REALLY enjoy every bite!! And, I move on from it. Living in the world means meals out and desserts and holidays...we don't need to demonise those foods...all that stuff is nice now and then. It's when you are doing it DAILY that gets troublesome. It's not a diet...it's for life!