It's Saturday night and you've just come from one of the best dinner parties ever—great appetizers and great company. You had a couple glasses of wine. Okay, they weren't on your meal plan, but you've been good all week, right? You can deal with it. You stayed away from most of the hors d'oeuvres except for the vegetable tray. You only took one bite of truffle and gave the rest to the Ficus tree in the corner. But then you get home and you're still hungry. You forgot to eat your salad at lunch and missed your apple before dinner. Maybe a snack? Why not, it's the weekend...

Stop and picture a big traffic light in front of you – it's red.

Dieting can be challenging, and often the hard part is being able to recognize when slip-ups are leading to more. So, here are a few warning signs you might want to look for. The goal is to avoid compounding these slip-ups so you don't feel so guilty or frustrated that you say it just isn't worth it.

Red Light #1 – Using food as a reward

Has this gone through your mind? "I deserve a treat for doing so well on my meal plan." You know what, you do deserve something—but try not to make it food. Rewarding yourself for doing well can be great motivation, but beware of the spur of the moment rewards that are often also high in calories.

Green Light – Plan non-food rewards ahead of time. Write down your goals and make these the only rewards you get (so you better make them good enough).

Red Light # 2 – Skipping breakfast

If you have never been much of a morning person, this can be an easy habit to fall into. A large cup of coffee seems to tide you over until lunch. You're not getting hungry in the morning, so it doesn't seem to hurt.

But there are a few dangers here. The first being that you are setting yourself up for disaster later in the day. You may end up hungry, but worse, you may start rationalizing foods that are not on your meal plan. "Well, I didn't eat breakfast, so I can have a drink or two after work." The calorie count may be the same, but you have just replaced healthy calories with empty calories that don't provide nutrition. Not to mention the fact that even one drink can do horrible things to a person's willpower. The other danger can be you are actually slowing your metabolism down by skipping meals. You want to get your body accustomed to burning food calories throughout the day, not just at the end.

Green Light – Order breakfast items like NutriSystem granola bars that are easy to carry and can be stored at work. Keep the fruit bowl at home stocked and leave your car keys in it. Do anything to grab an apple and not an apple fritter.

Red Light # 3 – No snacks on hand

You forgot your banana and ended up with a bag of cheddar popcorn. Not having a snack on hand may mean you need to plan ahead a little more.

Green Light – Take some time the night before to figure out what you are going to eat the next day. Set it aside, ready to go, next to your car keys. By taking five minutes to plan, you help avoid eating high-calorie snacks the next day.

Red Light # 4 – Social drinks

Your intentions are pure when you go to happy hour. Mingle with friends, have some water or a diet soda. Then someone offers to buy you a drink and before your brain knows it, your mouth has just ordered a third glass of beer. What happened? What ever it was, it happens to all of us. While a couple of drinks might not have a ton of calories, the situation can lead to things like appetizers, bar food, and late-night bingeing.

Green Light – A good trick when you go out can be to get a glass of water before you start to chat with friends. This way your hands are full and people are less likely to offer to get something for you. Diet soda with a lemon wedge is also a great disguise for its rum and Coke look-alike.

Red Light # 5 – Tired of yogurt

Your fat-free milk servings are important for both nutrition and for keeping you full. But, when the mere sight of yogurt makes you cringe, you may have to make a change.

Green Light – Think about some other dairy alternatives that are simple and easily stored at work. NutriSystem chewy fudge bars are great or how about a single serving of low-fat cottage cheese or string cheese? Variety can keep you on track.

Red Light # 6 – Not eating salads

You're not a rabbit and no one wants you to be. Humans should not live on lettuce and carrots alone; that's all there is to it. The problem is that salad with your meal is crucial to making sure you have a balanced meal plan and keep from getting hungry. Like skipping meals or snacks, leaving salads out can make you hungry later on.

Green Light – Try adding things like cucumber and spinach salads to your meal plan or combine your salad with your entrée (like turning Beef Tacos into taco salad). Keep adding variety to your day.

Red Light # 7 – Going out to lunch

Do you have two or three lunch entrees left over in your desk at work? If you do, it might be a sign that you should re-think your decisions. Have you been going out to eat with co-workers? Have you been skipping lunch because you got busy?

Green Light – Schedule to exercise at lunch and leave 15 minutes before everyone else does. Put yourself in the position to succeed by not being around when people are asking who wants to go out for Chinese.

Red Light # 8 – "I'll exercise more to make up for what I ate."

Oh, these are very, very bad words and almost all of us have uttered them at some point. The problem is they assume you will have motivation to exercise on the same day you lack the motivation to stay on the meal plan. Which you might, but you might also just chalk the day up as a loss and promise to be good tomorrow.

Green Light – Don't allow yourself to trade off parts of your plan. Think of each part of your weight loss program as standing on its own. You either do one piece or you don't.

Red Light # 9 – "I slipped up at lunch so I'll just start my diet over tomorrow."

If dieting were like Gone With The Wind, tomorrow would be another day. Inexplicably, many tomorrows never come when it comes to dieting. The morning arrives and your motivation is low. The rationalization comes, "I missed yesterday anyhow, and I'll just take one more day off." You can probably guess how the rest goes.

Green Light – Start over immediately with your next meal or snack. Get yourself back on the meal plan. Don't tempt fate.

Red Light # 10 – Late night cravings

This could be a sign that you haven't eaten all your portions and can lead to snacks that somehow look so much better after 9:00 pm. A satisfied craving can easily be followed by a morning when you feel bad about yourself and think it's just not worth it. Don't do this to yourself.

Green Light – If you are hungry at night, try having a cup of hot tea or chugging a glass of cold water. Both help to fill your stomach until you go to bed. Or brush your teeth right after dinner. It works!

In the end, it's worth it to struggle through the slips and learn from them. After each one, return to your meal plan without trying to modify it or compensate for something else you ate.

Say to yourself, "Okay, that happened, but I still know what to do – and I am going to do it now." Everyone hits red lights, so do what comes naturally—pause, look around, think, and then continue on towards your goal.