You have the basics covered, and I will interject that while manipulating carbs is a proven way to lose weight they should be a part of your diet. Even with the paleo structure, fruit is paleo and has carbs. There are a number of things you'll have to take a look at and be honest with yourself:
- How active are you?
- What kind of activity are you doing?
- How balanced are your meals?
- How often do you deviate from your eating plan?
- How much body fat do you have? Is 170 even a reasonable goal?
- How much stress do you have in your life right now?
If you aren't losing weight right now it's clear that something has to change. The hard part is figuring out what's wrong. If you are mostly sedentary, you will probably have to increase your activity. However, if you work out six days a week for 2 hours each day you may be doing too much. I'll cover these in more detail below.
Activities
Both frequency and type of activity are important. Too much activity, or too much of the wrong activity can increase your body's level of stress to a point where you are just flooded with cortisol and your pituitary glands are constantly firing. That's a bad thing.
- You should be doing some strength training. Barbell, dumbbell, body weight, kettle bell are all useful tools when trying to lose weight. Go for moderate weight, and more reps.
- You should be doing some conditioning work. 20 minutes medium intensity steady state a day, or 15 minutes of HIIT 2x/week is enough.
- You should limit your activity to no more than an hour at one sitting.
If you have any sports you like to play, it makes the exercise a lot more fun and useful if you do things that support that sport.
Nutrition
You are going to have to be brutally honest with yourself. How often do you grab a quick "little something" from the candy bowl at work? If you don't log what you eat, start doing it. It's most useful and important when you hit the plateaus.
- Make sure all your essential nutrients are covered (amino acids, vitamins, minerals, omega-3s).
- Make sure your macros have some balance. Carbs help you do the activities you need to do, so they do have a place.
- Make sure you are eating enough, but not too much.
You will do much better when all your nutrients come from real food. Supplements are for filling gaps when you need to hit your macro goals, not for replacing meals. Your body does better when it is in proper hormonal balance. Some changes are outside of your control, but your body does react to what and when you eat. What you eat can set off either good chain reactions or bad ones.
If carbs are under-represented, you'll probably need to increase them while decreasing something else. Same with protein and fats. For example, testosterone is manufactured from cholesterol, and a proper amount of saturated fat in your diet helps your body manufacture the needed amounts. Another example would be prolonged lack of carbs can cause the body to convert any free testosterone to estrogen (which can increase weight).
If your meal plan is good, but you don't stick to it well enough you have to change your behavior. See how long you can stick to your plan before you cheat. When you cheat turn that day into a whole cheat day, and then try to beat your previous streak. Alternatively, schedule minor treats every time you lower your body weight another couple pounds. The important thing is to have a plan you can remain faithful to without feeling deprived.
Goals
Good measurable goals are important, but try to use goals that help you accomplish some end game. For example, if you want to look like a fitness model then you'll need to make sure you have a decent base of muscle while you lower fat. If you just want to look jacked, you'll need more muscle and lower fat. If you just want to be healthy, you want to target either a healthy (<20% for men) or athletic range (10-15% for men) of body fat.
If you are 190 with 15% body fat and wanted to get to 10% body fat then 170 would be too low. Take time to get your body composition measured. That will give you some real data to set your goals from.
Stress
The body's response to stress is to adapt to it. In some cases the stress is something we want. For example, the stress of lifting weights causes your body to build muscle. In other cases the stress is bad. Things like not enough food, looming deadlines when you are behind schedule, worry, etc. all cause a fight or flight response which increase the catabolic state of your body. When the body is catabolic it can pack on pounds and catabolize muscle in the process of dealing with the stress.
- Identify any cause of bad sources of stress (include caffeine abuse, poor diet, major life events, commuting, etc.)
- Find out what you can do to reduce unwanted stress (reduce caffeine use, simplify your life, plan alternate routes, etc.)
- For things you can't change, try to find ways of dealing with it better.
Your body is designed to have periods of catabolism and anabolism. They help you stay healthy, and modern lifestyles tend to emphasize a catabolic state. Your goal here is to restore balance.
TL;DR
If you hit a plateau, then what you were doing is no longer working. You have to try something else. Do a little thinking to figure out what the most likely culprit is and make changes to address that.
