Why I don’t think low/zero carb diets are the way forward

Low carb, or ketogenic diets as they’re often referred to, have become hugely popular in recent years as celebrities and other high profile individuals have endorsed them for their weight loss and fat loss benefits. The principle is simple, the body will use whatever fuel source is readily available. Normally that would be carbohydrate, however on a low carb diet the body quickly burns through its carbohydrate stores and is forced to switch over to burning fat. This makes the body more efficient at using fat as a source of fuel. The miraculous weight loss results seen from this style of diet are not because your body is burning through huge amounts of fat, it merely comes about from the energy deficit that arises because you’ve cut an entire food group out of your diet.

So here’s why low carb diets can work for some people:

  • They create an energy deficit. This is the reason for any weight loss regime regardless of the fuel source. You can lose weight on a diet based mainly on carbs and protein if you want as long as the rules of energy balance are observed. If energy expenditure is greater than energy intake then you get weight loss and probably fat loss.
  • Fat and protein have a more satiating effect than carbohydrate, so even though fat contains 9kcal per gram compared to carbohydrate’s 4kcal per gram you probably don’t need to eat as much of it to feel full. This feeling of fullness will help to contribute to energy deficit as you won’t be as inclined to snack throughout the day.
  • The body becomes better adapted to burning fat. If you eat more fat you will burn more fat, purely because that’s all that is available to the body. This probably isn’t hugely significant to the everyday dieter as any energy deficit will create weight loss, but for an aesthetics athlete focused primarily on body composition and conditioning this might play an important role.

For a fairly sedentary individual, low carb might be a more feasible option. At rest or during very light activity is when the body is in fat burning mode, to preserve the carbohydrate stores in case they’re needed for a high intensity burst of activity later on. This is a survival adaptation that dates back to the days when we had to hunt for our food and fight dinosaurs and stuff. Chasing tigers and fighting dinosaurs is fairly exhausting work requiring the quick release energy provided by carbohydrates, how’re you supposed to catch your dinner if you’ve used up all of your carbs whilst at rest?

Now here’s the controversial bit:

I don’t think low carb is the way to go.

For a start, ketogenic diets are awful! Take it from someone who lived low carb for ages before finally coming to my senses. They make you feel lethargic and severely lacking in energy, give you headaches and don’t even get me started on the cravings that lead to epic, macro devastating binges! Bagels and Nutella are firmly back on the menu for me as a week of successful dieting can be ruined by a ginormous calorie surplus brought on by binge eating all of the things that you’ve denied yourself.

Feelings of failure begin to creep in, combine those with your increased irritability and short temper and it’s a recipe for disaster. As a consequence of this, you’re more likely to give up on your diet and end up regaining the weight you’ve lost and some. This can lead to yo-yo dieting, not a healthy habit by any means! Although it may seem extreme, disordered eating habits and clinically diagnosed eating disorders such as anorexia nervosa and bulimia can all stem from restrictive eating which then becomes obsessive.

The next big reason why I don’t fly the flag for living la vida low carb is because of the negative effect on performance. This is probably less important to those who already live a sedentary lifestyle, but for anybody who regularly engages in exercise or physical activity, particularly high intensity work, low carb is pretty bad news.

With low carb comes feelings of lethargy and reduced energy, meaning you may not train to your full potential. This is incredibly important when it comes to activities like weight training. The whole point of weight training is to build muscle, this muscle is more metabolically active at rest than the equivalent quantity of fat. More muscle = a higher basal metabolic rate. In simple terms that means the more muscle you have the more calories you use at rest. If you’re not training to maximum capacity due to having less energy then you probably won’t build as much muscle. This means you expend less energy throughout the day just by being alive.

There’s a similar effect on habitual, everyday physical activity. If you’re tired from having no carbs then your energy expenditure is likely to decrease, therefore meaning that you burn fewer calories throughout the day, especially when engaging in the low intensity type activities that generally use fat as an energy source.

Similarly….. Ever tried doing a really long run without carbs? No? I have and wouldn’t recommend it. I’ve never seen a chubby long distance runner and they eat so many carbs it’s untrue! Numerous studies have shown that athletes perform better with carbohydrates than without, so it goes without saying, if performance is your goal carbohydrate needs to be included in your diet.

No energy, tiredness, mood swings, irritability, a reduced capacity to train. It’s not looking so good for low carb!


- Charlotte Fisher


Nutritional Science Student