The danger of 1000-calorie diets: Are they actually safe?

You want to lose weight. Preferably in the next week and without any big effort. If you're aiming for this, it can be very tempting to drop your caloric intake extremely low. So called "fad diets" mostly consist of a 'formula'- a liquid shake, snack bar or a soup - that you consume regularly as a meal replacement.

Let me be completely clear here: Dropping your caloric intake to 1000 calories or less per day is a complete waste of time!

A high caloric deficit will definitely induce weight loss (mostly because you'll lose water and some muscle as well), but eating too few calories will also definitely hamper your results.

Never try such a diet on your own, only if it's prescribed and watched by a medical team (in cases of extreme obesity causing medical complications).

Why very-low calorie diets aren't safe at all


Getting gallstones is one of most common side effects of those low calorie diets.

Your body will lose weight quickly at the beginning. Your liver secretes extra cholesterol because of that, which leads to excess cholesterol, and combined with bile, gallstones can be formed.


You will only get very few nutrients when you are on such a diet. Hence, you'll most likely experience symptoms of nausea paired with fatigue and anxiety.

Being on such a calorie restricted diet for a longer period of time, may even cause visual disturbances as a result of your weakened state. If you experience symptoms like that, please visit your GP immediately!

Muscle loss

Of course you will lose muscle tissue when you're eating not enough calories. Your body begins to seek out new ways of acquiring energy. That's why it begins to use the muscle tissues instead of glucose in your blood stream for energy acquisition. This way, you'll look very skinny at the end. Preserving muscle mass is always very important in any diet!

Heart complications

Being on a low calorie diet can also lead to other dangers, such as heart arrhythmia, stroke and brain haemorrhage.

If you already have a history of heart issues, please don't consider a very low calorie diet. Your heart works so much better when your blood sugar levels are in check. A healthier moderate caloric deficit will give you enough energy to workout regularly and you'll get good quality sleep, which is important to keep stress levels down and to allow your body to regenerate properly.

Hormonal imbalances

Living on a heavy calorie-restricted diet means cutting down on essential dietary fats, which has the most calories per gram (9 kcal/g). Dietary fat is crucial for a proper hormonal function.

The first thing your body will do is to shut down all non-essential survival functions, such as the menstrual cycle or testosterone development. Some women might like the idea of heaving lighter periods or none at all, but keep in mind that it isn't healthy at all. Your hormone levels are thrown all over the place.

Furthermore, hormonal issues can lead to far worse health issues in the long run. This includes weakened bones and hypothalamic amenorrhea (when hypothalamus and pituitary fail to deliver signals to the ovaries, leading to a reduced production of oestrogen and progesterone).


Believe me, you really won't enjoy this.

Suffering from constipation means having fewer than 3 bowel movements per week.

When you are on a 1000-calorie diet, you're not likely to be consuming anywhere near the recommended daily intake of fiber.

If you're on a 1000-calorie diet at the moment, consider fiber supplements or substitute a fruit or vegetable for one with a much higher fiber content.

Sets you up for a major binge-fest

Eating too few calories will set you up for binge eating. Living on a huge calorie deficit will cause deficiencies in one or more nutrients at some point. Do you know that, for example sugar cravings are caused by such deficiencies?

Besides that, you'll feel stressed, fatigued, deprived and irritable, which may fuel those cravings until you finally give in.

You damage your metabolism

Dropping your calorie intake too low from one day to another, your body will instantly ring the alarm bell and slows everything down to save energy and protect vital organ function.

You will lose weight at the beginning (mostly water), but your weight loss will soon stall. And the worst is, as soon as you will go back to your maintenance caloric intake, you'll start gaining the weight back, and maybe even more.

The reason for that is because your metabolism is slower than it was before you started the crash diet.

Crash diets aren't sustainable

First, those extreme calorie-deficit-diets require extreme deprivation, it's unlikely you can stick to such a plan over time. And if you can stick to it, it's not fun at all.

Generally speaking, diets that dip below 1100 calories per day are very difficult to adhere for a longer period of time. It's nearly impossible to get all the essential nutrients your body needs in order to work properly. And it gets worse the more calories you burn.

Please stop googling for "fast weight loss diets" or "how to lose weight in 3 days". You didn't put that extra weight on in 3 days, so you aren't able to lose it in 3 days. Look for more sustainable ways to live healthier and to lose weight by making healthier decisions. This shouldn't be a change that lasts for about 3 weeks and then you go back to your old habits.

Incorporate more healthy habits into your lifestyle on a weekly basis. Even baby steps are steps in the right direction.

Start by taking a walk every day for half a hour. Then fill your fridge with more veggies, cut out processed food, eat out only 2 times or so per month, start meal prepping. It's really not that complicated, especially when you start slow.

How to lose weight healthier

It is no hidden secret that watching your calorie intake is the key to reach your weight goals. You need to eat less calories than you burn. Carbs won't make you fat! Dietary fat will not make you fat! Too many calories make you fat!

For a healthy lifestyle it also matters where those calories come from. They should be made up as much as possible of whole, unprocessed foods, combined with quality protein, complex carbs and healthy essential fats.

Furthermore, I would always recommend to start working out. It's not necessary for weight loss, but you will feel great. Best would be weight lifting. Start with compound exercises, like deadlift, squats, benchpress and military press to work on your overall strength.

How many calories should you eat?

We designed a calorie calculator, which uses one of the best formulas out there to accurately estimate the calories you need on a daily basis. Activity levels are expressed in a way that better suits most people's daily lives.

We used it both for ourselves and our clients and over time noticed it is very accurate.

Think about it. How can a 1000 calories diet make sense, when there are people who burn 2000 and people who burn 4000 calories per day? Everyone is different and therefore needs a custom meal plan and caloric intake!

Stick to a 20% deficit, no more and lose weight on a constant basis. Keep your muscle mass and look great in the end, not skinny and wasted!

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