As you are going through your journey of eating a very low-calorie diet (800 cal), it must be frustrating to find out that you are not losing weight. I had the same feeling while I was doing the 1000 calories diet. Hence, from my own experience and through searching around the web, I collected a lot of reasons that could help you out.
There could be several reasons why you are eating 800 calories and not losing weight. The first among these could be that you are miscalculating calories. Other reasons can be hormonal problems due to issues like pregnancy or not taking enough protein. But, the most common of these is that your metabolism has adapted to your new diet.
Still, there is a lot more to know. Hence we recommend you read this article entirely to understand all the tidbits required to fix this problem. Do make sure to share this article with your friends and family if you find it helpful.
Why we do not recommend the 800 calorie diet
Before providing you the exact reasons, we would like to point out that taking 800 calories a day is not suitable. 800 calories a day can result in nutrient deficiency , loss of a healthy metabolic rate , and in some cases, could lead to situations like gallstones. 
800 calories a day can also lead to a situation known as Yo-Yo dieting. This is a situation where once you lose your weight, you regain it back quickly, and then again, you prepare for dieting again.  Hence, a suitable diet would be around 1200 to 1500 cal.  By doing such type of diet, you can carry on for long and make it a part of your daily life.
Anyways, coming back to the topic. Here are the nine reasons why you are eating 800 calories and not losing weight: –
Calorie counting is a strenuous exercise. You have to correctly pick and choose what you eat based on the calories. And sometimes, it can go wrong.
Therefore, thoroughly check what you are eating and not base your assumptions on previously calculated data. For example, say an app that helps in calculating calories is saying that 100 gm of lasagna is equal to 163 calories.  However, every lasagna is made different.
You add different ingredients in different quantities and cook them for a different amount of time.
Hence the amount of calories is different as well. Therefore, to calculate the calories accurately, always count the raw ingredients rather than cooked once.
Make sure you have the basic idea of calories in mind:
- Carbs amount to 4 calories per gram.
- Proteins have around 4 calories per gram.
- And, fats equal 9 calories per gram.
For easy ways, you can use apps like Myfitnesspal and add all your calories consumed in a day to it. Remember that everything has its pitfalls. So, calculated according to the right calculations.
Your body has adopted
In the case of eating a very low-calorie diet, our body adapts to the situation by lowering the functions of our vital organs. 
Vital organs require a set amount of calories for every person so that they can function properly. This is known as the basal metabolic rate.  If you eat vastly below that, your body will reduce their functions like slowing down the heart rate, reducing liver functions, et cetera. 
To stimulate the metabolic rate, you need to do a lot of things.
How to increase your metabolic rate
- Increase the number of calories you are eating and add in a little bit of exercise. Regular exercise can definitely increase your metabolic rate  and therefore remove the weight loss slurp that is ruining your mornings.
- Taking a lot of protein can help, as well. Studies have found that taking protein results in a better constant metabolic rate , and that would help you in losing weight faster.
- Water can help, as well. Drink water can increase the metabolic rate by as much as 30%.  It also helps you in keeping full after a lite meal and therefore reducing weight. 
- Coffee can be a boon here. Coffee can stimulate your metabolic rate and reduce appetite.  So, start taking coffee with your diet to help you in reducing further weight. You can use skim milk powder to reduce the number of calories you take in every cup.
- Always doing dieting can also be a problem. It could lead to low glycogen levels, which could be responsible for this mess.  Therefore, having a cheat day can definitely help you out. You can also try to fix a day for a no-diet day. This will upset your metabolic system, and your body will not be able to restrict the organs to conserve energy. 
Too much stress
Stress can both be helpful and can be a determinant of your weight loss. It has been shown that stress can reduce your weight , but mostly, it will lead to weight gain  if you have constant stress going on in your head. So, avoid stress and use steps like yoga or meditation to help yourself out.
Eating a high carbohydrate diet
Eating highly processed foods that contain a high amount of carbohydrates can undermine your weight loss efforts. low-carb diets have been shown to reduce more weight than those with high amounts of carbohydrates.  Hence reduce the number of carbohydrates to a suitable level (somewhere around 45-65%).
Hormones can be a reason why you are not losing weight even after eating a very low-calorie diet. Hormones can diminish your weight loss efforts, especially if you are a woman.  Hence consult your doctor about your hormonal issues in case you are suffering from them and clear them out first before dieting.
In case you are on a high protein diet, which is unlikely in this situation, you could be gaining muscles. Muscles are denser than fats , and therefore, they could be a reason why you are not feeling the effects of your weight loss on your weighing machine. Use a clipper like this to check whether your muscles are growing or not.
Our weight can fluctuate as much as 1.5 to 2 kg per day.  There could be several reasons for this, but the main reasons are water retention and energy balance.  Therefore, wait a few more days to check whether it is just a fluctuation or you are not really losing weight.
You are missing enough sleep
Sleep is an essential factor in weight loss. If you are not getting enough sleep (say around 7 to 8 hours per day), then that could be a reason for less weight loss.  Try to reduce the amount of stress in your body and sleep as early as you can. You can also listen to pink noises which are known to help you sleep better. 
There are several factors responsible for why you are not losing weight even after eating so few calories. Read the reasons thoroughly and adapt them one by one in your daily plan. Still, if you have problems, try to change your diet from 800 calories to about 1000 or 1200 calories per day. You can also write to us using our contact us form, and we will help you out.