Once you decide on a diet strategy, these proven behavior-modification strategies will improve your odds of succeeding:
1 – Seek Out Social Support and Accountability
The people in your life need to be on board with your plan. Let your immediate family and friends know how important your fat loss goal is and suggest ways they can support (or at least avoid derailing) you, such as not offering you unproductive foods, not making a fuss when you choose goal-friendly options at restaurants, and so on.
You might also consider having a coach or an accountability partner that you check in with on a regular basis. This person need not be on a diet. He or she might actually be a coach that you pay. Either way, the two of you have a goal in common and support each other in pursuit of your objectives.
2 – Minimize Environmental Friction
Keep your pantry stocked with healthy food options you like and keep unapproved foods out of the house. Use smaller plates and dishes. Find restaurants that offer healthier menu choices than the places you normally frequent. Learn to actually cook.
The possibilities are almost endless, but the take-home point is to ensure that your environment facilitates your new habits as much as possible.
3 – Avoid Perfectionism
Fat loss isn't about being perfect, it's about being better. Assume that occasional lapses of judgment and willpower will happen and when they do, avoid self-judgment and simply move forward.
4 – Don't Stray Too Far Out of Your Comfort Zone
Intensity is great until you can't sustain it. Successful dieters typically lose between .5% and 1% of total bodyweight per week. If you have a significant amount of weight to lose (say 50-100 pounds), a slightly faster rate of weight loss is acceptable, at least initially. Otherwise, diet like a marathoner, not a sprinter.
One More Thing: Don't Say You'll Start On Monday!
Saying that is a sure sign they're full of shit! Joking aside, if it's truly important to you, you'll start now. I understand it might take you a day or two to get a plan together, but it doesn't change the point. Make today the day. Your only regret will be not starting sooner.