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Eat More, Get Big … the science!

You have probably heard of people in a ‘bulking’ phase who add an extra 2,000 calories to their intake through 2 donuts, a milkshake and half tub of ice cream. This will certainly usually give a mass gain! And with intense training maybe this will translate to predominantly lean mass. However, if you don’t have 6 hours a day to train, you don’t want a transient ‘fat’ phase and you are a little more concerned with the quality and blood sugar impact of the food you are putting into your body, you might have to be a little more scientific about how you approach a ‘bulk’.

First off, housekeeping. This article only addresses the nutrition for a bulk. I am assuming you have your resistance training regime nailed. If you don’t, then you need to address that first! I also don’t address supplements – those often favoured by the bulker are creatine and BCAAs … see my future posts for thoughts on those!

With that clarified, let’s talk food. Gaining lean mass with as little additional fat mass as possible requires even more attention to food intake and timing than losing mass. You need to eat more calories than you burn to gain mass, but you also need to pay attention to the nature and timing of your calories to drive a bias towards lean mass gain over fat mass gain.

Let’s break it down …


To gain mass total calories consumed obviously needs to be more than total calories expended. Simple law of physics! Current advice is typically to be in a 300-500kcal surplus per day, to support roughly a 0.5kg mass gain per week (McArdle et al 2015). For the typical individual going a lot faster than this will likely lead to much of the excess gain as fat mass … there will be a limit to how much lean mass any individual can gain in a week, whereas fat mass will just keep on accumulating with the calories!!

Macronutrients – how much?

In short, how much of your total calories should be carbs, how much should be protein and how much should be fats?

Protein is obviously vital to support lean mass gains … it is the building block of these gains!! Research indicates that between 1.6-2.2g / kg bodyweight per day supports maximal muscle protein synthesis when combined with appropriate training (Schoenfeld et al 2018). The variability likely stems from differences between individuals (more on that later) and also the proportion of lean mass an individual begins with relative to total bodyweight … the more lean mass, the more muscle protein they start with and so the more they need to replace and growth this muscle!

Carbohydrates. Are. Vital. Whatever the current trends may say, carbohydrates are critical for the performance of most athletes. And they are an asset to anyone looking to bulk. Carbohydrates provide the muscle glycogen to power anaerobic activity, i.e. most of the strength training designed for lean mass gains. All else being equal, if a muscle has more glycogen it can produce more energy to power more intense and longer duration training, and therefore further strength and lean mass gains. It is a positive feedback loop!! If you train for more than 1 hour a day, over 6g/kg bodyweight of carbs is recommended, according to sporting bodies in the UK and overseas (see position statements by the American College of Sports Medicine, the International Olympic Committee and the English Institute of Sports for commentary relating to energy intake in general, and its division across the macronutrients).

Fats then provide the remaining calories!! Athletes are typically advised not to drop fat below 20% of total calories, and not to exceed 25%. The lower limit being advised based on the amount of fat needed to function effectively as a human and support consumption and absorption of fat soluble vitamins. The upper limit to enable sufficient calories to be given to protein and carbs, rather than a ‘problem’ with high fat per se!!

Macronutrients – what sort?

The protein in our muscles contains all amino acids. This means we need to provide our muscles with all amino acids for them to grow. Some of these we can make ourselves from other amino acids. However, there are 8 essential amino acids that can only be obtained from the diet. Dietary protein will all 8 essential amino acids in sufficient quantity are termed ‘complete’ proteins. To effectively gain lean mass, you need to eat complete protein sources. All animal protein is complete. To obtain a complete protein from plant sources you will need to mix and match, as no single plant protein source is complete – combining legumes and wholegrains, for example, will create a complete amino acid complement.

Now, carbohydrates. I believe that sugars should be avoided on a bulk, except immediately post training. Eating sugar, particularly without a non-sugar carb, protein or fat eaten alongside, typically causes a rapid blood sugar spike and the release of insulin to bring blood sugar back into the normal range. Whilst insulin does promote the uptake of glucose into cells for use as an energy source and for storage as glycogen in muscle and liver, it also activates the pathways to turn excess glucose from the blood into fat for storage. After a sufficiently intense and long training where muscle glycogen has been depleted, the glucose and insulin response may be favourable (assuming glucose is not eaten to excess!), to support glycogen replenishment in the muscle. Aside from this, I would stick to complex and starchy carbs, including potato, rice, bread, as well as vegetables.

There is currently no evidence that the type of fat eaten impacts lean mass gains. This may be because no one has really looked at it yet, although I can’t immediately think of a reason why the type of fat would have an impact!! As such, standard guidelines apply. Avoid trans fats (synthetic fats), eat a lot of monounsaturated fats, eat saturated fats and avoid cooking with the vegetable oils that will oxidise on heating creating the types of fatty acids you do not want in your body!!

Timing of Food Intake

The focus here is timing of protein and carbohydrate intake. Research indicates that regular protein intake across the day supports muscle mass gain (Phillips et al 2016; Morton et al 2018; Reidy and Rasmussen 2016). This is likely because muscle protein synthesis remains elevated, if amino acids are available from food, for 24 hours post training and because the body cannot store amino acids, which means that if a large single dose of protein is eaten in a day much of the amino acids may be converted to glucose and other molecules before they can be used for muscle protein synthesis (Phillips et al 2016). On top of this regular intake, consuming 20-40g of a fast digesting protein such as whey immediately post training has been shown to have a further incremental benefit to muscle protein synthesis in multiple studies in both men and women (Macnaughton et al 2016; Schoenfeld et al 2018).

As for carbs, consuming 2.5g/kg bodyweight 2-4 hours before a heavy training session will help ensure maximal glycogen load in the muscle for use in the session. To maximally refuel muscle glycogen after training, the aim is to eat 1g/kg bodyweight in carbohydrate within 2 hours. When glycogen levels are depleted in exercise you get overcompensation, i.e. glycogen super loading, if you eat carbs soon enough after completing training … and as we have said already, the more glycogen you have, the harder and faster you can go through the day and the next training session, supporting further gains, and so on and so on until you are strong and swole as [insert favourite strong swole human]!!

For fats, there is currently no evidence to indicate that muscle mass is impacted by the timing of fat intake! Therefore, I would suggest avoiding it pre-workout to ensure that you do not feel sick (it is slow digesting!) and spreading it across the rest of the day weighted to when you typically feel hungriest!!


Okay, so we have covered the macros, but what about the micros?! Vitamins, minerals and other small compounds are vital for our bodies to function … including accessing the energy and muscle building blocks from food and subsequently building and powering muscle!!

As all the body systems are interconnected, for optimal health to train and perform the whole spectrum of micronutrients are needed. Of particular relevance to muscle are the B vitamins, calcium, vitamin D and magnesium. The B vitamins help access the energy from food in the muscle cells, and calcium and magnesium are both critical for muscle contraction and relaxation. And vitamin D is needed to absorb the calcium from our food! Together, these are provided by full fat dairy, eggs, red meat, fish, wholegrains, nuts and dark leafy green vegetables. The UK government guidelines also recommend that most UK residents (non-special groups) consider supplementing dietary sources of vitamin D with up to 10ug/day vitamin D3 between October and March, the months of least sunlight. This is because whilst vitamin D is not very available or sufficient from the amount of foods most of us eat; most of the vitamin D in our bodies we synthesize ourselves in sunlight. So … minimal sun = minimal vitamin D!


And so that is that, a whistlestop tour of bulking as I see it. We haven’t delved into the deep science, and I have not touched on the interaction with sleep or impact of hormones such as cortisol and testosterone … mainly because I think this is quite long enough as it is for one article!! In a nutshell, sufficient sleep and reduced stress supports athletic performance – as a start to learning more, I encourage you to delve into McArdle’s textbook referenced from this article.

And one final comment before I really do sign off: Every body is different. I know I have said this before, and for sure I will say it again … in the same way we all respond differently to alcohol, a kind comment, or ‘constructive’ feedback, we all respond differently to food. Our genes, lifestyle, age, gender, sleep state, stress etc all impact our metabolism and so whilst there are general principles that hold true, trial and error is always needed to work out your optimum nutrition protocol for whatever goal you currently have!!


Macnaughton, LS, Wardle, SL, Witard, OC, McGlory, C, Hamilton, DL, Jeromson, S, Lawrence, CE, Wallis, GA, Tipton, KD. The response of muscle protein synthesis following whole-body resistance exercise is greater following 40g than 20g of ingested whey protein. Physiol. Rep. 4(15):e12893. 2016.

Morton, RW, Murphy, KT, McKellar, SR, Schoenfeld, BJ, Henselmans, M, Helms, E, Aragon, AA, Devries, MC, Banfield, L, Krieger, JW, Phillips, SM. A systematice review, meta-analysis and metaregression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. J. Sports Med. 52:376-384. 2018.

McArdle, W, Katch, F, Katch, V. Exercise Physiology, Energy, Nutrition and Human Performance. 8th Edition. Wolters Kluwer Health, Philadelphia, USA. 2015.

Phillips, SM, Chevalier, S, Leidy, HJ. Protein “requirements” beyond the RDA: implications for optimising health. Appl. Physiol. Nutr. Metab. 41:565-572. 2016.

Reid, PT, Rasmussen, BB. Role of Ingested Amino Acids and Protein in the Promotion of Resistance Exercise–Induced Muscle Protein Anabolism. J. Nutrition. 146(2):155-183. 2016.

Schoenfeld, BJ, Aragon, AA. How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution. J. Int. Soc. Sports Nut. 15:10-15. 2018.

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