While perusing bodybuilding videos on Youtube, I came across an eye-opening comment on one of the videos:

There are no hardgainers. There are only under-eaters.

Is this true? Are people who find it difficult to gain muscle mass just not eating enough? From a scientific standpoint, this seems true. The law of conservation of mass and energy would refute any claim of a person eating more calories than he/she expends, yet not being able to gain weight. Let's make this question easier: in the absense of any debilitating gastrointestinal diseases, is it possible to eat a lot and still be classified as a hardgainer?


5 Answers 5


The body seems to be able to do a fantastic job of regulating its weight no matter how much or how little we eat. See this study (discussed in detail here) where lean people tried to gain as much weight as possible, tripling their calories and becoming sedentary. They had a hugely difficult time gaining, and lost it all quickly when the study ended.

The laws of physics you reference do not apply because the body is not a closed system. The body sweats, creates heat, excretes mass and more in ways that are difficult to measure. So yes, some people can eat enormous amounts without gaining weight.

  • 3
    The body doesn't necessarily extract all the energy from the food as well, so the actual number of calories 'consumed' may be much lower than estimated
    – Ivo Flipse
    May 11, 2011 at 12:02
  • @michael According to that article, I can't figure how people would be able to lose or gain massive amount of weight and yet people regularly do and maintain that weight. Feb 24, 2012 at 17:37
  • @maxbeaudoin Three things: first, you are wrong when you say people "regularly" maintain the weight. The vast majority of people can not maintain (I'm talking about 1+ years). Second, when the vast majority fail, there are still people who succeed, of course. Third, it's possible that some people have figured out how to do it, but that method has not been supported by science yet.
    – michael
    Feb 26, 2012 at 5:41
  • @michael thanks for answering, much appreciated! Feb 26, 2012 at 19:31

I believe that many people who consider themselves hardgainers have simply not tried eating and lifting hard enough. However, I don't hold this belief because of conservation of energy for the reasons michael's answer lays out.

I considered myself a hardgainer until I tried Starting Strength with (almost) a gallon of milk a day. The solution to not gaining weight is not to become sedentary and eat more. It's to lift heavy, then rest hard, and eat more than you think yourself capable. As Mark Sisson notes:

A hardgainer is often someone who doesn’t eat enough. Sure, genes play a role, but you can ultimately have a significant say in how those genes rebuild you. To a point. Eat more and lift harder to grab the reins.

In my limited personal experience, so-called hardgainers who get their diet, digestion, stress and heavy lifting in order tend to gain weight. Yes, not lifting, eating poorly, not sleeping, and digestive issues can derail that method. Yes, our bodies have a tendency to stay as they are. But I think many so-called "hardgainers" would find substantial success from dedicated eating and lifting.


This article from the StrongLifts website also echos that sentiment: Muscle Gaining Secrest - How to Gain Weight Fast. In fact it's a common theme among weight lifting sites. Anabolic diets (not to be confused with steroids) are designed to help you lose fat while still gaining muscle. According to the Glycemic Load Anabolic Diet (G.L.A.D.) they've got a lot of math for you to figure out your daily protein requirements, calorie requirements, and meal plans. Do note I'm not endorsing these diets, and have not tried them myself. I've been successful losing weight, so I haven't needed to gain it.

I think the most important contribution of the G.L.A.D. is the fact that muscles are only 600 calories. The advice not to overfeed calories is sound. If you are looking to gain lean body mass, the author recommends about 100-200 extra calories--not the whole 500 others (including me at one point) have recommended. Assuming the goal is lean mass, not fat.

Check out Medhi's recommendations and see if you are guilty of over training, under eating, etc.


I was what you would call a 'hard gainer' I have gained 7 lbs to in 2 weeks after monitoring my calorie intake and upping it substantially.

I believe it to be down to people not eating enough.

I know I'm going to gain fat with my current diet but I need it.

Here's a pic of my macros for the last 13 days.


  • 1
    Can you provide more explanation as to why it worked and the process you followed?
    – Matt Chan
    Nov 27, 2012 at 13:16

Strictly speaking, completely untrue. Anyone with short muscle bellies throughout their body will be a hardgainer no matter what they eat or what they do - your muscles can never gain more girth than they have length, as it would be impossible for them to contract otherwise. If you have universally short muscle bellies, the only two possible outcomes of eating a lot are remaining skinny as a rail or getting fat, but it will never lead to significantly increased muscle mass.

That said, muscle belly length isn't uniform throughout the body, so chances are everyone has some muscles with longer bellies that can be worked on to gain some extra size. The outcome usually won't be that aesthetically pleasing however - Ronnie Coleman is a good inverse example, he has generally large muscle bellies except for his biceps, which look quite silly compared to everything else. It would be the same if you have mostly short muscle bellies with one set of muscles with medium or long muscle bellies and looking comically large compared to the rest of you.

If you're someone like that, your best option is to just train for strength and endurance, and use the fact that you won't gain much bodyweight to perform well in sports that benefit from strength but contraindicate weight gain.

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