I've been attempting to do a high-protein calorie-restricted diet, while working out with the Stronglifts 5x5 program since early February. My follow-through for the Stronglifts part has been "decent". I've missed about a third of the workouts in total, but have managed to work out 2+ times per week on average. Yesterday I squatted 192 lbs.

I've been somewhat less successful with my diet. On average, I'm still eating more calories than I burn, I think. During the last 4 months my weight has increased from about 208 lbs to 216 lbs.

I'm wondering though - how much of that 8 lbs increase might be fat, and how much might be muscle? I'd imagine I must have put some muscle on because of my strength increases, but it's also easy to imagine that I've put on fat, because I haven't been sticking to my diet. Looking at pictures of me from a few months ago, I feel that maybe I look slimmer...perhaps? It's hard to be sure. Other people don't seem to notice a difference. My clothes feel a bit tighter, but I think that maybe adding muscle mass might lead to tighter-fitting clothes too.

In short - how do I know if small weight gains are muscle gains or fat gains?

  • Have you ever taken any measures? If you don't have a caliper, you can try pinching to get a rough estimate.
    – Ivo Flipse
    Commented May 12, 2011 at 16:43
  • @Ivo Filpse - I don't have a caliper, although perhaps I should get one. I do pinch myself. Using that method, I haven't noticed much of a difference between now and 4 months ago. I think maybe I'm seeing a slight fat loss, but the fact that my clothes are tighter and I weigh more makes me question my perceptions. Commented May 12, 2011 at 16:48
  • Well if you can pinch yourself, it means there's 'some' fat. I'm quite positive that you'd notice a significant difference.
    – Ivo Flipse
    Commented May 12, 2011 at 17:34

3 Answers 3


The most tried and true method of determining if you are gaining fat or muscle is to measure yourself. Even if you don't have a caliper, you can get a flexible measuring tape anywhere they sell sewing supplies. With one of those, measure the following:

  • Waist (at navel)
  • Hips (at largest point)
  • Chest (at largest point)
  • Biceps (at middle)
  • Thigh (for women) or neck (for men) (at middle of muscle)

In general, when you are gaining muscle and losing fat, you should see:

  • waist getting smaller
  • neck/chest/bicep getting larger (might shrink first while you are getting rid of excess fat)

The biggest indicator will be where you collect the most fat. Men tend to collect in their abdomen while women tend to collect in their hips and thighs. That varies based on body type and genetic factors. Botttom line is that you know where that area is.

If the problem area is getting larger you are gaining more fat than muscle. If the problem area is getting smaller, you are gaining more muscle than fat.

As to absolute values, all methods save one or two performed at doctors offices provide estimations based on different factors. The calipers are fairly accurate, if the person doing the measurements is consistent. Even if the absolute value is a bit off, the fact that it is consistent means you can adjust the number as needed. The electro-resistance methods are very dependent on your hydration, distribution of fat, time of day, water retention, etc. There are a couple methods that measure based on your density (i.e. water or air displacement).

Nothing is as easy as checking the tape measure. You may not be able to get a reliable body fat number, but you will be able to tell which direction you are going. I recommend checking about once a month. If you have to do it more often I recommend not measuring more frequently than once a week.

Personally, I have gained about 4 lbs since I initially lost weight, but have gone down a pant size in the process. That tells me I've reduced by body fat--I don't know exactly by how much, but it is down.

  • Gotcha. So if my clothes feel tighter that means more fat. Too bad. Well, from now on I'll be redoubling my dieting efforts. Commented May 12, 2011 at 17:35
  • @Joshua that often is only based on your waist size, so if you actually measure all your sizes, you'll get a better idea. There are some correction factors for the different measurement locations.
    – Ivo Flipse
    Commented May 12, 2011 at 17:43
  • 2
    @Joshua Carmody, particularly around the problem areas. If your clothes are getting tight at the chest, but not the gut/hips then it very well could be more muscle mass at the chest. The more a guy gets that V shape or a girl gets that 8 shape the more lean mass they have. Also NOTE: you very well may have put on more muscle. It's going to happen. However, you might have put on more fat as well. Commented May 12, 2011 at 18:34
  • Definitely. I weight myself regularly and use my belt buckle as indicator. I find that's fine grained enough for my needs.
    – Rob Gray
    Commented Dec 1, 2011 at 4:32

Usually when you put on weight, if you're exercising - particularly lifting - and eating a balanced diet (maybe even restricting your carb intake and increasing your protein and healthy fats) you'll get a ratio of 1lb = 70% muscle and 30% fat. After reaching your goal of say 10lbs bulk, 7 lbs will be muscle and 3 lbs will be fat. At that point, you want to cut your calorie intake by 750 untill you lose the 3 lbs.


At most gyms they can measure your body fat percentage for you using the 7-Site skin fold test. Have them do a measurement ones every four to 6 weeks to keep track of your progress. Likely you are gaining both muscle mass and fat mass, but unlike other suggested, the fat 'mass' isn't really that important, its the fat 'percentage' that counts. If you weigh 100kg at 35% and you gain 5kg of muscle and 2 kg of fat, than you haven’t gotten 2kg fatter, you'd have gotten 0.4% leaner.

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