As you start on this 12-week journey, it's essential to have a good plan of attack, so we consulted Gold's Gym Fitness Institute experts Adam Friedman and Robert Reames to develop a road map that can be your trusty guide (along with your trainer).

Whether or not you are signing on to the Gold's Gym 12-Week Challenge, you can jump-start a healthier life by following this checklist. With the help of Gold's Gym Fitness Institute experts Adam Friedman and Robert Reames, we developed the week-by-week list to help you stay on track to meet your fitness and diet goals. "But you don't have to follow each of these tips one week at a time," Friedman says. "Opting to incorporate tips from future weeks sooner in the process could yield faster results and increase your likelihood of winning a share of the $75,000 Gold's Gym Challenge prize pool."

Week #1

GET MEASURED: Go to your local Gold's Gym to get your vitals down on paper, and be sure to bring along shorts (men) or a bathing suit (women) for your "before" photo. It will help inspire you to get in shape and keep the momentum going.

• Weight:
• Waist:
• Thigh:
• Hip:
• % Body Fat:

CREATE A WORKOUT SCHEDULE: One of the biggest excuses for skipping workouts is a busy schedule. To make sure that doesn't stop you, get out a calendar and create a typical weekly schedule that includes everything from work hours and child-care responsibilities to your favorite leisure-time activities, then figure out where a daily workout can fit in. Also, look at where you can add in an "emergency" make-up day, in case a meeting runs later than planned or a babysitter calls in sick.

Any iPhone users can download the Gold's Gym Spotter app, which lets you set up a goal countdown, take progress photos as you go, learn exercises and more.

Week #2

PLOT YOUR DIET STRATEGY: Now that your goals are clear and you've created a gym schedule, it's time to focus on food. While exercise can kick-start weight loss, studies have shown that a proper diet is essential to dropping a lot of pounds—and keeping them off! Start by writing a three-day food diary. In it, record everything you eat (even that one doughnut hole you grabbed in a morning meeting). If your cell phone has a camera, snap photos of each meal to add to your diary. Then meet with a trainer or nutritionist to devise a weekly meal plan schedule. This should include:

• Times you are going to eat each meal:
• Breakfast options:
• Lunch options:
• Snack options:
• Dinner options:

Also, be sure to schedule grocery store trips at times when you won't be tired or hungry—shopping on an empty stomach can sometimes make you grab a high-calorie treat that isn't part of your diet plan. In addition, vary your menu by stopping at a farmers' market for fresh produce or stocking up at a local fish market.

Week #3

FOCUS ON REST AND RECOVERY: Getting eight hours of sleep each night is a must because your body burns fat more efficiently when it is well rested. And while it's important to crank up your fitness routine, make sure to give your muscles a break by scheduling recovery days when you either skip the gym or do a low-impact workout. In just a few days, you might notice that more shut-eye and your new fitness regimen will actually help decrease the amount of stress you feel on a day-to-day basis and increase your energy levels.

Week #4

INCREASE INTENSITY: You've got a great amount of momentum right now! You are about to have a full month of fitness under your (hopefully looser) belt. Now you're ready to kick up the intensity on your cardio routine. Treadmill fanatics should add incline to a walk or run, elliptical devotees can take the resistance up a notch, and bikers should add a 30-second sprint every five minutes. And talk to your trainer about how to measure your maximal heart rate so you can know whether your blood is pumping at full steam.

Check out these workouts for some ideas:
• The Power of Plyometrics
• Rev Up Your Cardio Routine

Week #5

NUTRITION DO'S AND DON'TS: If you haven't already adopted these diet tricks in your daily routine, this is the time to start. Here are six rules of thumb:

DO:
• Drink at least 3-4 liters of water a day.
• Replace artificial sweetener with stevia.
• Use sea salt instead of table salt.
DON'T:
• Wait on breakfast—eat that first meal within the first 30 minutes of waking up.
• Gobble down food on the go. Make meals last for at least 20 minutes.
• Fill up on diet soda. If you crave fizz, try flavored seltzer.

Week #6

MIDPOINT CHECK-IN: You're halfway through your 12-week challenge. This is when you should look at the goals you set at the start of the competition and assess your level of success. Think about getting remeasured by your trainer, and ask yourself these questions:

• Am I on track to accomplish the goals I set at the beginning?
• If not, what can I do to ramp up my efforts?
• Have I created a healthy environment for myself?

Week #7

SWITCH IT UP: Now that you've established a gym routine, consider trying some new activities. For example, swap out a treadmill session for a spin class, try a TGX class or add yoga to your workout schedule one day a week. (To find classes at your local Gold's, check here.) Varying exercises can stimulate muscle groups and keep you from getting bored.

These are some other workouts you might want to try:
• The Ultimate Leg Workout
• Back to School

Week #8

AMP UP YOUR METABOLISM: As you cruise into the final month of the challenge, it's time to put your metabolism into high gear. A better metabolism means you will burn more calories throughout the day (even when you're just sitting around) and will help you drop pounds faster. Here are three ways to crank it up:

1: Break up your meal plan and eat five small dishes a day.
2: Try eating spicier foods.
3: Incorporate multi-joint exercises that work more muscles at one time. (Watch this video to learn some basic moves or ask a Gold's Gym trainer for advice.)

Then be sure to read these articles for more tips:
• 7 Tricks to Transform Your Metabolism
• Top 10 Metabolism-Boosting Foods

Week #9

TALK WITH A TRAINER: Is there anything else you could be doing to get the most of the last month of the challenge? Set up a meeting with a trainer to go over your workout routines, diet plan and goals. Ask if there are new moves or group classes you should try that could add to your progress. There isn't much time left to take advantage of your competititve edge.

Week #10

MOTIVATION CHECK-IN: Congrats! You're almost to the finish line. Don't lose steam now—try these motivating tools to rev up your resolve:

• Create a Buzz: Tell your friends, family and coworkers how much weight you've lost, tweet it to your followers, post it on Facebook. Hearing "Congratulations!" will keep you getting back on the treadmill.
• Get Yourself a Little Something: Buying a new, smaller pair of shorts or yoga pants will remind you of all the hard work you've done and make you want to head into the gym to show them off.
• Sweat for It: Purchase a new music album on iTunes, order a page-turning novel or download a favorite TV show on a tablet—but only let yourself listen, read or watch while you're on a cardio machine. Creating small rewards can have big payoffs.

Week #11

WRITE A LETTER FROM YOUR OLD SELF: When you look in the mirror now, you probably do a double take. What would your old self have to say about that new body? Writing down those feelings of pride and accomplishment will help remind you why you decided to join the Gold's Gym Challenge and keep you focused during the last two weeks. Put the letter somewhere that you can see it every day—a sock drawer or jewelry box—as a reminder of why you decided to get in shape and live a healthy life.

Week #12

GIVE YOURSELF A HIGH FIVE: You did it! Now get over to that scale and see what a rock star you are. Doesn't it feel great? These past 12 weeks weren't easy, but the payoff is worth it. A healthier body brings with it more energy, confidence and a determination to stay fit. You have written your very own "Story of Strength," and we applaud you! Just remember: "This is a kick start for the rest of your life," Robert Reames says. You need to plan for the future. Sit down with your trainer to discuss how you can maintain your new body, then talk to your family and friends about your future fitness goals and how they can join in or support you. Think about signing up for a triathlon or a 10K race—keeping your competitive spirit alive can help you stay on track.