Carbohydrates, or carbs, have had bad press over the years and are often blamed for the obesity epidemic we now find ourselves in.


But is this fair? Are carbs the work of the devil or do they play a key role in your weight loss efforts. And, if they do, then how many carbs exactly do you need?


We’ll be answering these questions and much more in this article.



What are carbs and do you need them?


All life on Earth needs carbohydrates as a source of energy to survive (even fungi and bacteria).


And the truth is, carbohydrates are vital for us to look, perform and feel at our best.


This is because, not getting enough carbohydrates can lower important hormone levels (e.g. T3 levels, cortisol, and testosterone), which can make us feel sluggish, stressed and contribute to muscle loss which in turn impairs the way we look, perform and feel day to day. (1-6)


There are typically two different types of carbohydrates, simple and complex carbs.


Complex carbs need to be broken down into simple carbs for energy. This can help you to feel fuller for longer as it takes your body time and energy to digest, absorb and metaboise complex carbs (7).


Simple carbs on the other hand are very easy to digest, absorb and metabolise, they also taste much sweeter, which, when combined with being very quick to digest, makes them very easy to overeat.


This is great for when you’re doing a triathlon and need to quickly replenish your energy levels but not so great if you’re kicking back to catch up on some Game of Thrones.


This is why it is generally recommended that you eat more complex carbs such as oast, brown rice, brown bread etc. than simple carbs.


Whether you have complex or simple carbs, however, we can only store so much in our muscles and liver. So if we eat too many carbs, then the sugars are converted to fats and stored on our body…



Do carbs make it harder to lose weight?


The only way to lose weight is to consume fewer calories than you burn. If you want to know how many calories you need to lose weight you can use our simple calorie calculator here.


Energy balance - weight loss

This can be from too many carbohydrates, fats or protein and so no individual one is to blame, they are all equally important. 


It is the quality and quantity of each one which people typically find hard to work out, partly because of the large amounts of poor quality information we are exposed to every day.


In today’s world, however, it can be easy to overeat carbohydrates as they are easy to produce, cheap to buy and taste great! 


Next time you are in the garage, local small supermarket or restaurant, look at the number of carbohydrates on sale compared to protein and fats and this should give you a good indication of the situation.


Fats and proteins are no more important than carbs. However, foods high in protein are digested more slowly than carbs and so help us control our hunger better (8).


This is why “do you need carbs?” is the third and final question on our Health by Science plate. While most people find it difficult to eat enough vegetables and protein, having too many carbs is more often a problem than getting too few. Especially if getting plenty of fruit in your diet.

HBS plate carbs

The process in which carbohydrates are converted into fat is called de novo lipogenesis (DNL). However, studies have shown that this process is not easy for the body and so you have to eat a lot of them in order for this to happen (9-11).


So the question is how much is “a lot”?


How many carbs do you need for weight loss?


As we’ve already said, if you don’t eat enough carbs then you will feel sluggish, irritable and stressed. In fact the minimum recommended intake for carbohydrate is 130g a day for the general population, with the majority coming from fruits and vegetables.


But if you eat too many then you’ll obviously put on weight! Like most things in life, the poison is in the dose. 

poison in the dose

While the minimum recommendation is 130g, the optimal recommendation is  roughly 3 grams per kilogram of bodyweight (12-15). 


The more exercise you do however, the more your carbohydrate needs will go up. This is because our body uses the carbohydrates stored in our muscles for energy and if we don’t replenish these stores, we’re in danger of becoming sluggish, irritable and tired. 


As a rule of thumb for every 60 minutes of exercise you do (intense enough so that you could speak but you couldn’t sing), then you’ll need an extra 50g of carbs.

carbs and exercise

Overall it is wise to fill up on protein and eat fewer fats and carbs when trying to lose weight (16).


Furthermore, if you are running low on carbohydrates but your protein intake is good, then your body can actually convert protein into sugars to use as energy.


This is why the question “where is my protein?” is first on the Health by Science Plate above. If you don’t get enough protein when trying to lose weight, there is a danger that your body will breakdown your muscle tissue to use for energy.


This is not good, especially as you need all your muscle mass to help fight off an accelerated ageing process.



You can find out how much protein you need to help you lose weight by clicking here.



What does that look like in real life?


The most accurate way to keep track of your protein intake is to use My Fitness Pal which syncs directly with our app which you get free access to in our Free Weight Loss Kickstarter.


If My Fitness Pal isn’t for you then, fortunately, there’s another way…

carbs portion


Your hand can function as a good portion size guide and for carbs we use a cupped handful. Although not quite as accurate as My Fitness Pal, it’s easy to use, it’s relative to you (the bigger the hand the bigger the portion) and you always have it with you!

carbs in an apple
carbs in beans


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If you have tried dieting and are confused or overwhelmed by the huge amount of weight loss misinformation on the web, then try our weight-loss scorecard below.


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What are the best sources of carbs?


Now that you know the quantity of carbs that you need, it’s important to understand where the best quality sources come from.


Processing food isn’t inherently bad but in general, the less processing a food has been through the more chance it has of sustaining its nutrient density (17).


It’s also important to remember that foods are not inherently “good” or “bad”, there are just better quality foods which we should aim to eat more of and “poorer” quality foods which we should aim to eat less of when trying to lose weight.


carb sources


Can you eat poor quality carbs and still lose weight?


A diet missing poor quality carbohydrates is not a healthy diet. These foods taste really good and are there to be enjoyed. 


Can we live without them? Absolutely.


Do we have to? No.


In our opinion, the problem is that they used to be considered treats but now such foods are extremely convenient, and therefore, common in most people’s diets today. This can make change hard.


If we are able to make up 80% of our diet from good quality food, however, then you can get away with eating treats and still losing weight. So long as your calorie intake is low enough.


At first, this can be hard because these foods typically taste great and you will crave them. 


Amazingly though, our taste is plastic (meaning our cravings can change) and responds to the foods we eat regularly.


Understanding your nutrition requirements based on your goals and individual barriers is a key part of achieving sustainable weight loss, just like our clients below. 


Image of weight loss client Beth

“I’ve been working with Jamie since Feb 2019 and moved to Health by Science with him. I love working out at their gym, everyone’s super friendly.”


Over a 12 month period, David managed to lose over 10kg and record his lowest and healthiest weight in the last 25 years.


Image of weight loss client Lucy

Lucy used to think that people like her weren’t meant to exercise. Lucy has now achieved results she never thought were possible.


image of weight loss scales


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1) Danforth, E., Horton, E. S., O’Connell, M., Sims, E. A., Burger, A. G., Ingbar, S. H., . . . Vagenakis, A. G. (1979, November). Dietary-induced alterations in thyroid hormone metabolism during overnutrition. Retrieved from


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