@Rares
The TUT (Time Under Tension) role and importance as a factor for inducing muscular hypertrophy is... really misunderstood and misused.
Dr. Layne Norton explained in depth the issue about it in this video:
You don't have to watch it, but thing to know about it is most people are actually increasing their time spent in the gym and decreasing efficacy of their workouts with no benefit or even limiting their potential growth.
@Yourreputationisoutthere.c
Training:
I would recommend any 5x5 program, begginer athletes tend to do really well on them:
5x5 Stronglifts or more fresh (not necessarily better) Jason Blaha's 5x5 Novice Program or my favourite Mark Rippetoe's Texas Method, but the first two are better to start IMO. Keep it simple, adding weight to your lifts each week will increase the total workload and the training volume which is a primary factor to increasing muscle hypertrophy a.k.a muscle growth.
Focus on resistance training and cut out cardio if You don't find yourself gaining weight.
Food:
If You struggle to gain weight and happen to be called a hardgainer or have a body type of an ectomorph (the whole somatotype idea is a semi myth at best, invented & introduced by a psychologist William Herbert Sheldon almost 80 years ago).
What I find from working with people is they just have a small apetite and tend to think they eat a lot. When we actually start to measure their macronutrient intake and calorie input, it turns out they're eating below or at their maintenance - they were just undereaters, overestimating their food intake.
Here are the best tips that come to my mind right now and in fact, one of them has been given by @Leo Gura in a specific form, that I'm going to play with:
Which can be transformed into more universal rule: "Drinking your calories helps a lot"
It doesn't have to be whey protein, consuming anything in liquid helps You gain weight for 2 reasons:
1) It's easier to drink a cup of mixed oatmeal and veggies, whatever You like, than to eat the same amount on plate.
2) It doesn't make as You satiated which leads to You being able to eat more without getting feeling sick
Eat more calorically dense food like for example: peanut butter if You're allergic to dairy or find the type of food that You like and try to overeat on it.
(It wasn't a question about how to keep your blood markes or fasting glucose good, You want to gain weight - consume more calories. As long as 80% of your diet makes up to deliver fiber and necessary micronutrients, the other 20% has marginal significance).
If You're really into that (most people're not and find it boring unlike me), You could measure Your food intake by counting macronutrients or/and calories in MyFitnessPal for example. I'm just spitting ideas at You.
When it comes to meal frequency, You'll have to experiment as fewer meals (Intermittent Fasting) tend to change Your leptin (goes up) : ghrelin (goes down) hormones ratio which leads to decrease of apetite over the course of the time, so I would start with 3 - 4 meals, since saying to eat when You're hungry wouldn't do much because that's probably the same thing You've been doing and struggling with gaining weight - It wouldn't apply.
Generally try to eat often.
Inner game:
When I first started lifting, my main reason for taking actions in direction of building muscle & getting fit was shallow, long story-short - I just wanted to look good for girls. If that's remained as the primary motivating factor I would've probably given up after a month.
But the funny thing is that I really started to enjoy the grind, looking in the mirror, loading more weight to the bar, being able to help in mundane stuff like carrying groceries, moving big ass sofas without needing any help and carrying your drunk, half-conscious friend out of the club to make sure he won't get robbed or beaten. Working out to look great may be shallow, but so is wearing makeup, taking selfies, and grooming of any sort. Pick your shallow.
Looking good naked is cool, but nothing compared to being stronger than You were.
For me, a young, growing man, strength is a value associated with the personal growth, exploiting your potential in one more area.
By being stronger, You can bring more to the table, be more useful.
Plus after almost every session I'm in state of mind close to the one obtained through meditation - like still water after storm.
Okay, so if You don't want my Woo woo stuff , I will give You very specific reasons and benefits associated with lifting weights, which are based on scientific studies (I will probably regret that, since everybody would require a link to every single study. You know how many there are? ^.^):
It reduces cancer risk considerably and increases the chances of survivng the cancer. Factors below also have impact on cancer risk reduction.
Moderate amounts of regular resistance training and aerobic activity have been shown to reduce risk of diabetes to a very high degree.
e.g. http://archinte.jamanetwork.com/article.aspx?articleid=1307571
Is associated with better bone mineral density and/or bone width, which amongst others means it protects You against osteoporosis or osteopenia and suggests lower risk of physical injury
e.g. http://www.ncbi.nlm.nih.gov/pubmed/9809388
Having more muscles allows You to eat more, unlike adipose tissue, lean tissue burns energy - You are burning more calories (increasing TDEE - Total Daily Energetic Expenditure), just by having more muscle mass instead of fat.
It increases insulin sensitivity, which is also associated with better nutrient partitioning and how well your body utilizes food in some cases, helps also people with impaired glucose tolerance
e.g. http://www.ncbi.nlm.nih.gov/pubmed/20351587
It reduces resting blood pressure, decreases low-density lipoprotein cholesterol and triglycerides, which is good for longevity and avoiding cardiovascular diseases
e.g. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1756170/
If You really want to dig deep, there is so much information, You'll be confused and overthink stuff to a degree it'll become procrastination.
Start doing, pick a program, eat what seems to be healthy and slowly gather information or You'll kill yourself with thought processes and questions like:
"Does whey protein has to be cold, since enzymes are denaturalized in over 40 degrees?", "Is my current aminoacid ingestion timing optimal for getting maximum muscle-protein-synthesis?" or "I don't know if doing a ketogenic diet will help me preserve muscle mass more than high carb".
Don't worry. Don't get obsessive. It's okay to be wrong and the details will not affect the big picture. Do the best that You can with all that You have and don't worry about the rest.
Science is science, some guy's story on the forum is just a story.
You have to find Your own reasons and deeper value derived from engaging in those actions.
What's Your WHY?
The bigger the reason, the better.