Why You Should Eat More Protein to Lose Weight

***DISCLAIMER: I’m not a doctor or registered dietician, and the advice in this article should be taken as advice and not as a prescription. Get the all clear from your doctor before starting any big dietary/lifestyle changes***

When we think about losing weight, we tend to think about carb or fat intake - which makes sense as many popular diets focus on them too (eat less of one, more of the other). What we tend to forget about is the third main macronutrient, protein, which is a shame as it’s also the most useful - especially if we’re trying to lose weight.

Protein has a few tricks up its sleeve that can make our nutritional endeavours easier or harder to pursue, and once we have a better understanding of them we can use them to work for us to make dieting a damn sight easier.


Like carbs and fats, protein is utilised in a number of process and structures in our bodies. However, the way protein is processed and how our body reacts to it reveals a few characteristics that we can use to our advantage.

Increased thermogenic effect:

The thermic effect of food (aka TEF, special dynamic action or thermogenesis) is the amount of energy it takes to digest and process the food we eat, accounting for almost 10% of the calories we burn each day moving around and staying alive. More complex foods take more energy to process, with protein being the most energy consuming, followed by carbs and then fats (with organic foods being harder to digest than processed/junk foods). So if we compare an organic protein snack with a processed fatty snack, even if they contain the same amount of calories on the packaging, we’ll burn a few extra calories from simply digesting the protein snack.

Doesn’t get stored efficiently:

Our civilisation has developed at an incredible rate, with food more abundant than ever in first world countries - but our bodies are yet to adapt to the this fact. Any extra carbs/fats that we don’t immediately need for fuel or recovery are stored away for later use (in fat stores and as glycogen in the muscles/liver), but excess protein meets a slightly different fate. While the amino acids that make up protein can be converted into energy to be burned, this is not an efficient process (using up more energy to process and store compared to carbs and fats), and some of the excess aminos will just be excreted as waste.

Increased satiety (feels more filling):

Eating a meal with a large amount of protein will typically leave us feeling fuller than a meal with little to no protein in it, so we’re less likely to pile more onto the plate or snack later. The mechanism behind this appears to have a hormonal nature as well as simply sheer stomach space filled, but either way we can use this full feeling to signal the end of a meal or to resist snacking just because there is more food available. Less snacking means less calories coming in, which means potentially more fat loss (if we’re in an appropriate caloric deficit).


Looking at this handful of characteristics of protein it seems like the perfect food to help us drop fat, yet so few people utilise it - opting for stinky salads or boring biscuits instead. This stems from the idea that bodybuilders have a high protein diet and are freaky muscular, so if we eat a high protein diet we too will end up freaky muscular. Nothing wrong with liking or disliking the absolute unit look, but this thinking is a myth that needs to be dispelled as it gets in the way of improving our health and our relationship with food.

This idea has a classic “correlation vs causation” root. In other words, high protein diets are indeed a feature of hulking bodybuilders, but there are many other features contributing to the outcome of giant muscles - namely focused and intense hypertrophy training over a period of YEARS, a highly specific diet and lifestyle geared towards recovery/building muscle (the majority of time spent in a caloric surplus), and there may or not be steroids involved that speed up or amplify the muscle building process (regardless of possible detrimental effects they can have on the rest of the body). There are also individual genetic differences that can contribute to how quick/slow this process is, but generally speaking it’s still going to take a while to add on a tonne of muscle mass from wherever we start from, so we don’t have to worry about “accidentally” becoming a bodybuilder.

ZAP myth dispelled! But that now opens up another line of thinking - if we don’t perform super intense exercise 7 times a week, and excess protein isn’t stored or is converted to energy in an efficient way (more calories burned), why don’t we just have a super high protein diet and eat as much as we want? Well our bodies need a range of nutrients, big and small, so having a diet of just protein would leave us open to a world of problems due to deficiencies and imbalances, so we still need to get our carbs, fats and veggies in. What we need is some kind of balance between enough protein to help us reach our goals, and enough extra nutrients to stay healthy enough to enjoy reaching these goals.

As a general recommendation, aiming for 1.6-2.8g of protein per kg of body weight per day is a solid place to start. For example, an 80kg person would aim for 128-224g of protein per day.

This is a pretty big range, accommodating anyone trying to maintain as much muscle mass as possible while the body burns through the fat for energy - if you’re dieting hard and progressively lowering the weekly calories you may want to increase the proteins as you go to reduce muscle breakdown (without the caloric surplus we’ll have a hard enough time repairing muscle, nevermind building more of it). However, in order to get the benefits of a high protein diet (the increased TEF, satiety and less excess energy stored), we only need to aim for a minimum of 1.6g of protein per kg of bodyweight.

For all the meat lovers, there are studies that have looked into even greater daily protein intakes for resistance trained individuals (4.4g per kg of bodyweight - 352g of protein for our 80kg person!) that have taken the body into a caloric surplus, but due to the characteristics noted above they didn’t end up with more body fat by the end of the study period (Antonio et al, 2014). However, 4.4g of protein per kg of bodyweight is pretty tricky to stick to as our diet would be mostly protein with little other food types - and if a diet is had to stick to we are likely to quit or fall off the wagon sooner or later. Instead, we need to find an amount of protein that works for our preferred diet and situation, that allows us to stay in a caloric deficit.

Organic or whole food options are the best, but it’s not the end of the world if you have some more processed food or protein powder in there - just know that they’re not quite as filling or nutritious as whole foods.

If you’re tracking calories, each gram of protein has 4 calories of energy in it, so times the grams of protein by 4, take it away from your caloric requirements for the day and devote the remaining calories to carbs/fats however you see fit (just remember carbs have 4 calories per gram and fats have 9 calories per gram).

For an easier way to measure, use your hands - guys aim for two fist sized portions of protein per meal, and ladies aim for 1-1.5 fist sized portions per meal. While it’s not quite as scientific as measuring/counting macros, it is quick and easy to use.


When we’re building muscle we need to get in a caloric surplus to have plenty energy to both recover from training and then assemble new muscle. The knee jerk reaction is to train hard and prioritise getting as much protein as possible - more building blocks means more recovery/potential muscle, right?

Wrong - unlike fats/sugars, we know that our bodies don’t store amino acids, any excess being chucked out or converted to energy in an inefficient manner. So once we have enough aminos to rebuild and construct more muscle, any additional protein essentially goes to waste.

If you have a big appetite or money to burn this might not seem like a big issue, but if you’re like me and eating loads is troublesome - this extra protein takes up stomach space that could be used for carbs/fats that are used for recovery and energy. These are just as important for building new tissue, and give us the energy we need to crush training in the first place.

Interestingly, this means that when we’re trying to build our bodies we might have to dial back our protein intake if we’re going nuts with chicken and rice. The 20 year old me is shouting blasphemy, but 20 year old me also prioritised calf raises over squats - looking at those getaway sticks for legs I think I’ll listen to the science on this one.

The minimum amount of protein we should aim for is still about 1.6g per kg of bodyweight per day, but if we have intense training we should aim for closer to 2g per kg of bodyweight per day to make sure we have enough aminos for recovery and building new muscle. As long as we get a sufficient amount of carbs and fats in each day (keeping us in a caloric surplus), any extra protein is a bonus.


Protein is easy to come by for omnivores, with both a wider range of options and the fact that animal proteins are complete proteins - meaning each source contains all the amino acids needed for various biological processes. With incomplete protein sources (plant based) we need to get more variety to obtain all the aminos. Eliminating animal proteins from the diet can make it a little trickier to get all the amino acids we need, but this just means a bit more imagination in our meals.

The following are not exhaustive lists, but will give you an idea of where to start. I’ve stuck to organic foods, but bear in mind there are a tonne of vegan protein shakes (pea, rice, soy etc) and vegetarian protein shakes (whey, casein, etc) as well as more processed foods that can provide additional sources of protein.



VEGETARIAN PROTEIN SOURCES (in addition to vegan sources)

Eggs - 7g protein per egg

Milk - 3g protein per 100ml

Cheese - about 25g protein per 100g (may vary depending on type of cheese)

Greek Yoghurt - 5g protein per 100g


Antonio J, Peacock C, Ellerbroek A, Fromhoff B, Silver T. 2014. The effects of consuming a high protein diet (4.4g/kg/d) on body composition in resistance trained individuals. Journal of the International Society of Sports Nutrition. May. pp 11-19.

BBC Goodfood. 2018. The best vegan protein sources. Available online:

https://www.bbcgoodfood.com/howto/guide/best-sources-protein-vegans [Date Accessed 5.5.19].

Healthline. 2016. The 17 best protein sources for vegans and vegetarians. Available online: https://www.healthline.com/nutrition/protein-for-vegans-vegetarians [Date Accessed 5.5.19].

Morell P, Fiszman S. 2017. Revisiting the role of protein-induced satiation and satiety. Food Hydrocolloids. July 68. Pp 199-210.

Paddon-Jones D, Westman E, Mattes RD, Wolfe RR, Astrup A, Westerterp-Plantenga M. 2008. Protein, weight management, and satiety. Am J Clin Nutr. May 97(5). Pp 1558-1561.

Westerterp K. 2004. Diet induced thermogenesis. Nutr Metab (Lond). Aug 1. Pp 5.