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What is a low-carb diet?
Don’t I need carbs?
What is low-carb good for?
What are the downsides?

What is a low-carb diet?


confused about low carb

The answer to this might seem obvious (it’s a diet low in carbs…duh), but there are so many “low-carb” diets out there that it can be easy to get confused – some are based on grams of carbs per day, some use a % of your total daily calorie intake.

Personally, I’m a big fan of the “% of daily intake” approach – people come in all shapes and sizes, and their bodies are going to be capable of dealing with carbs to a greater or lesser extent as a result. In this vein, I’d say that anything under around 25% of your daily caloric intake (if you’re not sure what this is, don’t worry – I’ll explain it later) from carbs would count as low-carb (certainly a lot lower than the average person’s diet).

However, if you do some research around the net, a lot of places like to use absolute values to define low carb. Some suggest that anything under 100-130g per day (about 400 calories) is low carb (and again, it’s certainly lower than average), while some prefer values under 50g a day (like Keto diets).

If you’re not actively trying to achieve ketosis (more on that later), the actual value doesn’t matter too much – as long as you focus on getting most of your nutrition from protein and fats, and focus on getting your carbs from starchy vegetables, you’re almost certain to be eating fewer carbs than the average person, and will be well on the way to improved health.

But don’t I need carbs?

carb rich
I keep hearing this, and it’s enormously frustrating.

Yes, our body uses carbs as fuel. They’re burned preferentially by the body because they’re so easy to process, so if they’re available, our body will use them. But that doesn’t mean that we need carbs, as some websites suggest (although the associated fibre and micronutrients that we get from some sources of carbs are pretty damn useful, so it’s probably best not to ditch them entirely).

Let me explain.

In case you weren’t aware, there are three major macronutrients that our bodies use for fuel – protein, fat, and carbohydrates. Protein and fat are essential to us – protein is made up of amino acids, which are the building blocks of muscle, facilitate communication between cells, catalyze reactions, etc. If you’ve heard of “essential amino acids”, those are the amino acids that our body can’t synthesise – we need to consume food that contains them (i.e., protein). Fats, likewise, are essential – the body uses them to absorb certain vitamins (A, D, E, and K), as well as using them to maintain normal hormone functioning. Fats that the body can’t synthesise are known as “essential fatty acids”.

However, there is no “essential carbohydrate” – in the absence of carbs, our bodies are capable of breaking down protein or fat molecules to provide the body with all the energy it needs.

Basically, we can get by without carbs. Not that I recommend ditching them completely, mind you – just because our bodies can continue to function without them doesn’t mean that they do so at optimum efficiency. But it’s good to know that we can, if we want, go very low carb with few negative effects.

What is a low carb diet good for?

If you’re here, reading this, then odds are you’re looking for a diet to help you lose weight. A little, some, a lot – it doesn’t matter. Low carb diets are fantastic for helping people shed unwanted inches/pounds/insert your measure of choice here. Check out the Keto sub on to see some people’s transformations.low carb weight loss

So a low-carb diet is great to help you drop some weight. But it can also provide a number of other related health benefits, including:

  • Lowered triglycerides. If this doesn’t mean anything to you, trust me – it’s a good thing. Triglycerides are fat molecules that circulate in the blood stream, and high levels of them are considered a strong risk factor for heart disease, and can indicate the presence of “metabolic syndrome”. Cutting carbs, counter-intuitively, reduces triglyceride levels in the blood.
  • Increased levels of HDL (the good cholesterol). Higher levels of HDL are correlated with lower risks of heart disease – so increasing your HDL levels (which you do by eating fats) is a good thing. Even better, the ratio of triglycerides to HDL is considered another predictor of heart disease risk. So, if you’re lowering one (triglycerides) and increasing the other (HDL), you can be reasonably certain than your risk of heart disease is decreasing.
  • Reduced appetite. When compared with low-fat diets, low-carb diets tend to result in a greater reduction of appetite. That’s a good thing, because when you’re dieting, the last thing you want is to be hungry all the time. The natural appetite suppression that comes with a low-carb diet means fewer cravings, and a natural tendency to consume fewer calories (promoting weight loss).
  • Reduced blood glucose and insulin levels. This is particularly important for people with insulin resistance or Type 2 Diabetes. A low-carb diet can cause large drops in blood sugar – without all that carb consumption, your body doesn’t need to produce as much insulin. Indeed, some studies have found that after several months of low-carb dieting, many Type 2 diabetics were able to reduce or eliminate their need for medication (IMPORTANT NOTE: If you are currently taking blood glucose medication, or are concerned about your blood glucose or insulin levels, talk to your doctor first, before playing around with your carbohydrate intake).
  • Reduced blood pressure. As with high levels of triglycerides and high levels of LDL (that bad cholesterol), high blood pressure can be an important risk factor for many health conditions. Thankfully, low-carb diets tend to reduce overall blood pressure, reducing your risk of heart attacks, strokes, etc.
  • You feel better. This one is obviously subjective, but a study comparing low-carb versus low-fat diets found that individuals on the low-carb diet reported significantly better moods than did those on the low-fat diet. So chow down on whatever delicious fatty food you prefer and feel good about yourself!

There you go – a whole bunch of benefits for throwing out the bread and starting a new, carb-reduced existence. But I promised to be unbiased, so here are the not-so-positives…

What are the downsides of a low carb diet?

Disclaimer: Most of these apply to very low-carb diets (i.e., <50g/day), with the goal of entering ketosis. If you’re on a diet with reduced carbs (e.g., under 100g/day), but not entering ketosis, you’re less likely to experience a number of these.

  • Induction flu. induction-fluThis one, very specifically, relates to people attempting to enter ketosis with very low carb consumption (under 50, and often under 20g of carbs per day). Also known as “keto-flu” or “carb-flu”. It occurs as a result of your body adapting to using fat as its primary fuel, and symptoms can include headaches, dizziness, nausea, mental fog, muscle cramps, and general weakness. Honestly, it can suck. However, it is only temporary, and some of the worst of it can be ameliorated by keeping your electrolyte levels high (a nourishing chicken or beef broth can be great for that). The worst of it is generally over within a few days, although some symptoms can linger for up to a few weeks as your body adapts. Push through it, though, and be rewarded!
  • Decreased strength and endurance. Again, this is temporary, at least for endurance (indeed, some evidence suggests that low-carb diets can actually be beneficial for endurance sports that don’t require short bursts of maximal output). But if you’ve been lifting weights, prepare to struggle to hit those same numbers for a while.
  • Constipation. Again, this one is easily managed. Depending on how low-carb you’re going, you may still get enough fibre from vegetables to keep yourself regular (I should note that fibre, while technically a carb, doesn’t count towards your daily carb-limit). However, if you’re being militantly low-carb, you may find that you need to take supplements to keep everything working fine. Flaxseed or psyllium husk are both great supplements for this.
  • Potential irritability. As with the previous effects, this one is usually temporary, and likely a result of combined factors: the physiological shift from using carbs to fats as fuel, and the psychological strain of giving up chocolate (let’s face it, the second one is probably the main culprit). Thankfully, as you adapt, sugar-cravings will reduce, reducing the desire to bite peoples’ heads off (or to just shake them down for candy bars).
  • Dehydration. Going into ketosis causes the body the shed a lot of water – in fact, this water-loss can account for huge early weight-loss (but it doesn’t represent fat-loss – don’t be fooled). As the body breaks down glycogen in the muscles, it releases a lot of water, which you end up peeing out. As a result, it’s very important to stay hydrated – you will likely need to up your water consumption fairly dramatically to compensate.
  • It’s probably less ideal for someone wanting to lift weights. Our bodies are good at converting from using glycogen (from carbs) to fat as fuel. However, energy from fat is released more slowly, which means that high-intensity stuff (lifting heavy weights, sprints, etc.) get a lot harder – they rely much more on quick energy catabolisation, such as that which you’d get from glycogen. As a result, if you want to go low-carb but also want to engage in these types of activities, you may need to consider a carb-cycling approach, where you periodically have “carb refeeds” (basically eat a bunch of carbs to provide your muscles with some quick energy).

So yes, there are definitely some side-effects to a low-carb diet, but for the most part they’re temporary and can be planned for/managed. If you’re sensible about eating low carb, including managing your fibre and micronutrient intake, then a low-carb diet should come with a whole bunch of positive health outcomes. If you treat it as an excuse to eat nothing but steak and cheese…well, that’s when you’re going to run into problems. Thankfully, if you’ve read this far then you’re far too educated to do that, so you’ll check out some of the other resources on the site and learn how to do low-carb properly! Awesome!


Low-carb diets are any which restrict carbohydrate intake to a level at which the majority of one’s calories are coming from proteins and fats. Carbs, despite many claims to the contrary, are not essential for day-to-day functioning (at least, not at the level at which they are often claimed to be). Low-carb diets come with a whole host of really important health benefits. And, while there are some negative side-effects to a low-carb diet, they are largely either temporary or can be managed with planning and forethought. So there is very little reason not to try a low-carb diet today – check out my reviews of some of the popular ones, work out whether there’s a particular one you’d like to follow, and get to it!

Disclaimer: There are certain populations for whom a low-carb diet may not be ideal. Most of these are people with pre-existing metabolic conditions, but people who have poor fat digestion/impaired liver function should also be wary. For the full list, check out and click the link that mentions contraindicated medical conditions.