18 year old skinny male. Low calorie to high calorie diet.

Only time will tell, don't crank the calories too fast too early. You don't want to put on lots of fat.

Please tell me you're lifting weights? What programme are you following?

What's your current percentage bodyfat?

That's a good amount. Stick where you are and be patient - your weight will probably spike up a few pounds with glycogen and water initially, and then you should see a somewhat steady gain. And get doing some form of resistance exercise Good luck.

That's a good amount. Stick where you are and be patient - your weight will probably spike up a few pounds with glycogen and water initially, and then you should see a somewhat steady gain. And get doing some form of resistance exercise Good luck.

This , Get your TDEE and add 500calories to that . Id assume 3000-3500 daily would yield some solid results over a few weeks/months.

Lift heavy , eat lots , I personally would avoid cardio if I was in your situation . Why burn away extra calories when you don't need to.

The trick is to pack on the weight, and then turn the fat you develop into muscle. Strength training for you at the moment would probably not be the best idea because it is significantly harder to build up your muscles from nothing. Do a good amount of cardio, and eat a lot of foods with fats and carbs (not trans fat though. You want to put on some weight not have a heart attack xD). After you've put on fifteen or so pounds that's when you may want to start strength training and trying to maintain your weight. At this point though, I don't think you have any reason to try to diet and watch what you eat. Just be cautious and eat a lot. Also late night eating will surely pack on the pounds for you. Good luck my friend. -Ryan

Utter and absolute nonsense.

Fat cannot be developed into muscle, and people new to exercise are the most able to quickly add muscle.

I'm speaking from my personal experience. Everyone is different and I imagine everyone losing weight/build muscle differently as will.

The trick is to pack on the weight, and then turn the fat you develop into muscle. Strength training for you at the moment would probably not be the best idea because it is significantly harder to build up your muscles from nothing. Do a good amount of cardio, and eat a lot of foods with fats and carbs (not trans fat though. You want to put on some weight not have a heart attack xD). After you've put on fifteen or so pounds that's when you may want to start strength training and trying to maintain your weight. At this point though, I don't think you have any reason to try to diet and watch what you eat. Just be cautious and eat a lot. Also late night eating will surely pack on the pounds for you. Good luck my friend. -Ryan

Utter and absolute nonsense.

Fat cannot be developed into muscle, and people new to exercise are the most able to quickly add muscle.

I'm speaking from my personal experience. Everyone is different and I imagine everyone losing weight/build muscle differently as will.

While it is kind of you to offer advice, there is so much wrong with your suggestions, regardless of your personal experience. To suggest eating a high caloric diet while NOT strength training is a quick way to create a fat body. Sure, people build muscle differently, as in different food and exercise choices, but the body is simply incapable of converting one type of pre-existing mass into another. Fat cannot be converted to muscle, and muscle cannot be converted to fat.

You can certainly do some bodyweight exercises until you get the okay for lifting. There are several excellent books including 'you are your own gym' and 'bring it' , the latter of which is by Tony Horton who produced the p90x system.

But if you start slow with weights, I do not see it should be any issue. Just be sure to find a trainer initially to make sure you get your form right.

Weigh yourself first thing in the morning on an empty stomach and then start consuming enough calories that you gain about .5LBS per week. Weigh yourself the same day each week. I know .5 doesn't seem like a lot but it will add up over time. If you are not gaining, simply eat more. It's that simple.
Get on a solid lifting program. Stronglifts, Starting Strength, All Pros Beginners or 20 Rep Squat routine (there are many variations). Stick with one program for at least 12 weeks. Don't go from routine to routine just because you hear that X routine will give you Y results.
Edit: since you had a hernia years ago, slowly introduce exercises such as deads and squats into your routine. Work on forum first then weight. Gauge how you feel.

One of the posts above is a bit wonky. We all know fat cannot be "converted" into muscle. However, I have taken Biochemistry, and I feel the need to point out something...

Don't forget that fat is a stored energy source, and can be oxidized to provide energy for muscle growth. If you have two people and both are struggling with eating enough calories to build muscle but are getting enough protein in their diet, I've noticed that the one with a little fat does seem to have an easier time building muscle than the one who is 5% bodyfat and ripped. The reason for this is simple: without sufficient calories, you cannot build muscle. A chubby person has a buffer...the fat can be burned and used to fill in for the missing calories. I think that's all that poster was trying to say, but he didn't articulate it the way he wanted to. Sometimes it's hard for really light people to eat enough when they're exercising, because they're not used to eating a lot (since their metabolism has slowed due to decreased bodyweight). This is also why sometimes an overweight woman will build muscle faster than a skinny guy, even though she lacks the testosterone. In fact, I've seen chubby people who work out and eat at maintenance "accidently" build muscle because of this effect. i.e. "accidental bulking". They lose their fat in the process, of course, as it's being consumed to create the energy needed for muscle growth.

Another version of this accidental bulking is when a person who strength trains simply accidently eats too much for an extended period of time but without realizing they are eating too much, and so they get fat...but they also gain muscle without realizing it. I've seen many men and women do this. Then when they start to cut (diet), they have a good amount of muscle under the fat and they look fairly muscular after the fat loss. Most skinny people have never eaten enough to do this, so they have less muscle to begin with.

None of this (having ample bodyfat versus not) matters, however, if you're actually getting a sufficient caloric surplus in your diet. Muscle gain also has nothing to do with speed of metabolism or body type. It's all calories in vs. calories out. You just have to get enough for your body, plain and simple. (And work out properly of course!) The good news is that you soon get used to eating more. Some of us need more calories than others. It's a good idea to track calories using MFP. Otherwise, there's no way to know how much you're eating each day.

Finally: to build muscle, your body has to be on the verge of fat storage (i.e. the "well fed" state). No way around that. Unless, of course, you're just a super lean muscle building genetic freak who doesn't store much fat (which we all hope we are!)

To rigorous and exercise program can defeat your weight gain and even cause you to loose weight.

If you're not eating back all exercise calories, yes.
Ditto for if you're creating a lot of catabolic hormones due to the excess exercise.

I'm 18, 5'4 and only weight like 6st 8lbs. So I'm a pretty small underweight guy. This is my second day of my new diet change. I went from a minor 1500 calorie a day diet to a 3500 calorie diet. The new diet consists of peanut butter and Nutella sandwiches, plenty of eggs and a lot of milk and other stuff of course. My metabolism is very fast. When should I start seeing results? Should I boost it up to 4000 calories?

What results exactly do you want to see?

With your stated program, and from latter post of no strength training, the only thing you will see is fat gain. And you won't even be able to effect where that happens.

Well, actually, try to get really stressed out over gaining fat, and you may help it to gain in your belly, but that's about it.

It depends how strenuous his everyday life is. If he's tossing hay bales, for instance, he will be fine without added strength training (but will need even more calories to offset the burns). Again, tracking intake using MFP or another calorie/macro nutrient tracker is key to succeeding.

Btw, I'm mystified by these nutritionists who decide it's best to double someone's intake all of a sudden. Why does one need a ~1,000-calorie surplus? 200-500 calories has been proven to suffcient for most individuals. Pretty sure there's no way around fat gain when using a diet that adds an extra 1000 cal.

There's some good advice and some really bad advice here. Don't do cardio. Do 5min warm up on an elliptical or how you like and that's it. This is because the calories you burn you have to eat back. You WILL gain some fat, that's normal. Nutella is ok but it has sugar and sugar is a building block of fat. What helped me was a weight gainer protein mix. Per serving (2-3 scoops), it provides 50-85g protein and 450-1000 calories.

Experience: Went from 130lbs to 150 in a few weeks. I outgrew jeans and they'd be too tight when I'd try to wear them out after buying them. I didn't eat right back then but I probably went from 800 calories/day (didn't do **** and ate mcdonalds once a night) to 3000+...I was 21 back then.

Check out www.stronglifts.com .... great program that focuses on heavy lifting. This + 3000 calories = personal records just recently.

If you have been avoiding (s)training your back because you are worried about your past hernia, you can always start up more slowly with some bodyweight back-exercises, see how it feels, build some strength. Most important thing you can do for your back is that when you exercise, is that you keep excellent form to prevent injuries.

I am of the opinion that you should look at your Total Daily Energy Expenditure (TDEE) and realistically add 500-1000 calories (not more) to that, while combining this with heavy lifting (or some other strenuous strength-building program). Realize that it's hard to add more than 10 lbs of real muscle a year, unless you are in a growth spurt . Then measure and track your progress before changing your eating or lifting routine.

Be willing to have patience. My sons are both in the 20-22 age range and I have encouraged them to look at the long term, because trying to add more than this often becomes excess weight (Read: fat) that adds no benefit. I'm assuming that you don;t have any health issues relating to your weight.

Both of them are eating 500 calories excess and are seeing meaningful results in weight gain as they are both lifting heavy regularly. Cardio is also a big part of their overall routines, so weight is slower to be added, but the lean muscle added has been consistently in the 8-12 lbs per year over the last few years.