Do you have a good understanding of why your diet didn't work, or why it may have worked initially but you couldn't sustain it?  Millions of people diet, and dieting is a Billion dollar if not Trillion dollar industry.  The culture of body image and weight loss means big bucks for people looking to capitalize by marketing diet products and programs.
You've probably tried a few different diets and achieved similar results, or perhaps you experienced divergent results but a common regression to your original starting point - perhaps you ended up gaining more than you lost.  This is a common problem.  It's been said that we don't have trouble losing weight - people do it everyday.  Rather, we have trouble keeping weight off.  Why?

The reason....

Please watch, listen, and share the video lecture.

"I'm so unmotivated", "I need a new routine", "I need something different", "I got bored of my old program"...

Do these sentiments sound familiar?  I hear this stuff all the time, and it's one of the many things that drive me batty. 

I've been training for over 20 years, and I've been training others for just over a decade, so believe me when I tell you I've heard it all.  I know how the average person perceives exercise; I know their good habits and I know their bad habits; I know why most people start and stop exercising; I know the success and failure rates; I know what separates them from me.  I know this from experience, and I know this from the abundance of exercise physiology, psychology, behavioural, and epidemiological research.

There's always some new article or book that convinces people of the obscure missing piece to their daily regimen that will magically be the one thing that sends them over the top of whatever obstacle(s) have been keeping them back.  But I, as well as the scads of coaches who actually work with people one on one (not just write books or articles), know that those who fail to accomplish their goals, whether fitness-based or otherwise - do so because they neglect the fundamentals, the basics - not the nuances.

Fundamentals account for 90-95% of success, whereas nuances are largely unnecessary components of the bigger picture.  A machine can be "finely tuned", but it can nonetheless perform its job as directed without fine tuning.  Fine tuning just means it does the job with less wasted energy.  The irony when it comes to a goal like weight-loss is that wasted energy IS the goal.  The less efficient you are, the more energy you expend, and the more weight you lose.  In contrast, getting fitter is a process of becoming more efficient at a given task - whether physically (e.g. stronger muscles move weight easier), or physiologically (e.g. more and larger mitochondria and RBC's allow you to use oxygen more efficiently).  This is why, in part at least, you find it difficult to maintain your weight-loss momentum from month to month.  You've picked all the low-hanging fruit (the easy weight), and now you have to work a bit harder and/or longer to get more weight off.

If you have a fitness goal, which also accomplishes health goals by proxy, you only need to worry about doing the basics, repeatedly, over a long enough timeline to see your goals through, and with the intent of doing so as best you can while acknowledging that you can always improve:

1. Do not overfeed yourself - or starve yourself
2. Do not restrict or avoid foods or food groups
3. Be active, regularly - but not obsessively
4. Get enough sleep
5. Avoid "all-or-nothing" attitude towards life
6. Pay attention to what you are doing, and learn from your mistakes
7. Strive for excellence; do the best you can; do better over time

Do NOT worry about silly, dichotomous thinking and biohacking BS such as:

1. Should I eat all my carbs at the start of the day or at the end of the day?
2. Should I sleep all at once or take micro-naps through the day?
3. Should I eat low carb or low fat?
4. Should I go Vegan or Carnivore?
5. I should count every calorie...or...Calories don't count if I do this diet!
6. Tracking food is obsessive compulsive, so I'm going to intermittent fast instead and create a binge eating disorder - yay!
7. I should only do only the BEST exercises, otherwise exercise isn't worth doing!
8. I'm 44, overweight, poor diet, high BP, and no training experience or formal guidance in exercise.... time to start training for that marathon and eating only meal replacement shakes!
9. I need to eat only low-glycemic carbs, less than 25g at every other meal, across 10 meals per day, between the hours of 12pm and 8pm, paired with only lean or vegan protein, every other day on my rest days where I only do fasted, low-intensity steady-state cardio first thing after I wake up.  Unless I'm on a carb load refeed - in which case I eat only 2 meals per day, immediately after my workout if 1 hour or less, otherwise before my workout if 1 hour or more, at 1500 calories each, containing 200g of mixed carbs each meal, with fats as low as possible to speed up gastric emptying and maximally stimulate insulin to "drive nutrients into my cells", along with at least 0.1g per kg/bodyweight of leucine to stimulate muscle protein synthesis from a protein source that is either only lactose free, gluten free, egg-free, free-range, grass-fed, organic, and ethically butchered....unless it's Saturday - in which case YOLO!!!!!!!!

We need to stop this nonsense.  These examples are all indicative of behaviour that attempts to circumvent long term commitment to the process, in favour of an easier way to the prize.  There isn't one.  This is true in life, as well as fitness.  For this reason, I find it typical that those who fall for these shortcuts and empty promises of success without effort tend to display a similar kind of half-assed approach to their jobs and home life.  Your "new routine" should be seeing your current routine through to the end.  Are you bored with progress?  If you are bored it's because you're just going through the motions, and in the beginning that was enough to keep you interested.  If you're bored it's because you never identified what your goals were, and thus you don't know why you started your routine in the first place.  That or you need a reminder - progress is the goal, not entertainment.

How you do fitness, is how you do life, work, and family - "If you don't have time to do it right, when will you have time to do it over?" - John Wooden

Q: I know you lift weights, but what do you do for cardio?
A: I lift weights faster
Don't let anyone convince you that "cardio" is a physical state you achieve in the absence of weights - whether it be on a bike, a treadmill, or a skipping rope.

Cardiovascular Demand VS. Oxidative Metabolism / Aerobics
Have you ever finished a challenging set of deadlifts, maybe a 5x5 at 80% 1RM, and realized that even though you took 2-min rest in between sets that your heart is now racing like a jack rabbit?  That's cardio.

Cardio doesn't mean spandex and headbands, and it doesn't mean bobbing up and down on ellipticals for 45min or more.

Cardiovascular training means placing a demand on your heart to increase its rate of contractions (HR in BPM) as well as its stroke volume (SV: amount of blood ejected by left ventricle with each contraction) in order to feed (and flush) working muscles.  Arnold constantly spoke of of "the pump", that feeling of blood-filled muscles creating pressure underneath the skin.  When you lift weights, blood is directed to the working muscles.  As you continue to lift weights (duration), or increase your pace (speed), or increase the weight (intensity/load), this demand for blood increases and SV and HR go up.  Moreover, the heavier the weight, the more mental acuity required.  This increased focus and alertness stimulates and is facilitated by increased HR.

Aerobics is essentially any activity that lasts longer than 90 seconds.  Beyond this point, oxidative phosphorylation/cellular respiration becomes the dominant energy system during continuous exercise.  As exercise duration increases, heart rate and respiration tends to increase.  In most cases, we stay at a pace where we can maintain a constant and steady rate of breathing and heartbeat. 
Engaging in this type of exercise with relative frequency is typically sufficient to improve cardio-respiratory function, mitochondrial density, and oxidative capacity.
However, adapting to exercise and seeing improvements means you have become fitter than you were, which means your aerobic training needs to be more intense to see continued improvement, or to even maintain aerobic fitness (metabolic rate may decrease as much as 5% per decade after puberty). 
By definition, the greatest demand you can place on the heart lies closest to the anaerobic threshold - the point at which the aerobic system cannot produce energy fast enough to address the energy demands placed on it.  If you've ever done interval training with a work-to-rest ratio of 1:1 or less rest, then you know what this intensity feels like.

According to a study by the Journal of Applied Physiology, a low-volume, high-intensity interval protocol of 60s:60s work-to-rest at 90% Max HR over 2-Weeks resulted in improved glucose control and metabolic health:

• reduced avg 24h blood glucose concentration
• reduced 3hr post-meal blood glucose concentration
• increased mitochondrial capacity (~20%)
• increased enzymatic activity (~227%)
• increased GLUT4 content (~369%)
  • transports glucose across muscle cell membrane

TOO MUCH, TOO LITTLE:
You don't want to be doing an hour of aerobic training each day, but then again I wouldn't advise repetitious high-intensity interval training (HIIT) each day either.  The key is balance.  You have two facets to your autonomic nervous system.  The (1) parasympathetic system is responsible for stimulation of "rest-and-digest" or "feed and breed"activities that occur when the body is at rest.  The complimentary (2) sympathetic nervous system's primary process is to stimulate the body's fight-or-flight response. 

When organizing your training it's important to schedule days that facilitate the parasympathetic response, allowing time to "rest and digest" - a Rest Day.  The term rest is relative.  Sometimes you do indeed require a day of absolutely no activity to optimize recovery.  The rest of the time you should aim to, at the very least, alternate training days of higher intensity with days of lower intensity.  It also helps to avoid stimulants (e.g. caffeine) on these days.

Example:
MON - 1hr of weight training paired with 10-15min of HIIT

TUES - 30min of Low-Intensity aerobic exercise 
WED - 1hr of weight training paired with 10-15min of HIIT
THURS - OFF
FRI - 1hr of weight training paired with 10-15min of HIIT
SAT - 30min of Low-Intensity aerobic exercise
SUN - OFF

Sources:
Low-volume high-intensity interval training reduces hyperglycemia and increases muscle mitochondrial capacity in patients with type 2 diabetes. Jonathan P. Little, Jenna B. Gillen, Michael E. Percival, Adeel Safdar, Mark A. Tarnopolsky, Zubin Punthakee, Mary E. Jung, Martin J. Gibala. Journal of Applied Physiology Dec 2011, 111 (6) 1554-1560; DOI: 10.1152/japplphysiol.00921.2011

As mentioned in the previous article:
Your bodymass directly influences your resting metabolic rate.  The more mass you have, the more calories your body needs to function.  When you lose weight, your requirement for calories decreases in tandem.  The other side of this coin is that the higher the proportion of muscle mass to fat mass you have, the more calories your body needs: the higher your metabolism.
Any weight-loss program that fails to include progressive weight-training is destined to fail long-term by not attempting to combat the reduction in metabolism due to reduction in body-mass.  Weight-training places necessary demand on the muscles to grow, or at least maintain mass.

POINT A:
So you need to weight-train, OK.  But is all weight-training hypertrophic (muscle-building)?  Yes and no.

• 50lb Goblet Squats x 50 reps will build muscle
• 100lb Barbell Squats x 40 reps will build more muscle
• 150lb Barbell Squats x 30 reps will build even more muscle

What's the reason?...the weight?  Partially.  The major factor is volume.

• 2500lbs total vol.
• 4000lbs total vol.
• 4500lbs total vol.

Even though the weight is increasing, the main determinant of your results is the total added work from example to example.

POINT B:
So squatting 150lbs x 30 reps is obviously the most effective choice here.  But if I just squat 150lbs x 30 reps two times per week for the next year, will I see steady improvement in my muscle-building?  Probably not.  Why?  

Adaptation. (click link for Basic Principles of Exercise Training)

Your body adapts to the work you do.  After 6 weeks of squatting the same weight for the same reps, your progress will have slowed or have begun to slow.  How do you combat this phenomenon on exercise physiology?

Adapt your training.  Example...
Week 1(A): 150lbs x 6 reps x 5 sets = 4500lbs
Week 2(A): 150lbs x 6 reps x 6 sets = 5400lbs
Week 3(A): 150lbs x 8 reps x 4 sets = 4800lbs
Week 4(A): 150lbs x 8 reps x 5 sets = 6000lbs
Week 1(B): 160lbs x 6 reps x 5 sets = 4800lbs
Week 2(B): 160lbs x 6 reps x 6 sets = 5760lbs

In this example, the total weight lifted progressively increases in a wavelike fashion, undulating upwards then downwards, then back up again a little higher.  This is (one form of) progressive resistance that takes advantage of the hypertrophic effects off increasing intensity/load, as well as the gradual increase in volume.  The wavelike periodization is ideal for preventing chronic maximum stress.  If going "all out" each workout you inevitably create a deficit in recovery, which impedes progress.

So even though there are many ways we may use resistance and weights in our training (see picture above), it doesn't mean that these are effective methods of muscle building or even muscle maintenance.  Because, like your caloric requirements, the stimulus required to trigger muscle growth is a moving target.  Changes in our bodyweight, our age, our environment, and even our sleeping behaviour can all affect how efficiently we build muscle.

The Journal:
Just like how you track your food, you should be tracking your training volume.  If you have someone special to create a program that is progressive by design, much of that work is done for you.  However, you should still keep a journal to make notes as to what weights are appropriate, energy level, instances of pain, any exercise modifications, or modifications based on how quickly or slowly you're progressing.