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What are Calories?

Many will already have an understanding of this, but due to some rather silly naming, this topic is actually slightly more confusing than it should be. Simply put, a calorie and a Calorie are not the same thing – a Calorie is equal to 1000 calories (cal), and when we refer to calories in food products, we actually mean Calories, aka kilocalories (kcal). So if, for example, you need 2000 Calories per day, this is actually 2000000 calories. A calorie is a unit in chemistry which is defined as the energy required to raise 1 gram of water by 1 degree Celsius, and is equal to 4.1868 joules (J). A Calorie, therefore, is equal to 4186.8 joules, or 4.1868 kilojoules (kJ). The reason I bring this up is because on nutritional labels, generally the energy is displayed both in Calories and kilojoules, and either can be used for the purpose of calculating your required energy intake (though generally Calories are used).

What is TDEE?

TDEE stands for Total Daily Energy Expenditure, and as the name would suggest, it is a measurement of the number of Calories you expend in a day. There are many different factors that can affect your personal TDEE (which I will summarise below), and it is quite important to have at least a rough approximation of what yours is if you want to lose, maintain or gain weight. There are numerous calculators online which provide an idea of your TDEE based on your input of a number of different factors, but these can only provide an approximation. At the end of this section, I’ll provide an explanation of how to work out your TDEE more precisely.

If you consume fewer Calories than your TDEE, you will lose weight, and if you consume more Calories than your TDEE, you will gain weight. Consuming Calories equal to your TDEE will maintain your current rate. This is the origin of the term ‘Calories in versus Calories out’, and this does hold true as a general rule. However, there are a couple of reasons why it either won’t hold true all the time, or why it isn’t particularly helpful advice for those looking to lose (or gain) fat.

  • TDEE takes no account of loss or gain of weight due to changing levels of hydration. As so much of the body is made up of water, there is a natural fluctuation to your weight based on your level of hydration, and this is totally unaffected by how many Calories above or below your TDEE you consume. As such, in the short-term, you can see weight loss even when consuming above your TDEE, or weight gain when consuming below it. This is one of the reasons why it is a bad idea to obsess over your weight on scales when dieting.
  • While Calories in versus Calories out is a good way to approximate whether you will lose or gain weight, it is not particularly useful for working out whether you will lose or gain fat (which is one of the main motivating factors behind starting a diet). More and more research is suggesting fat loss is dependent on insulin sensitivity as opposed to just Calorie intake, and this is one of the reasons why simply cutting Calories can be a bad idea. I won’t go into detail on why this is the case in this guide, but for those interested in the topic, please see here and here. I’m also happy to discuss this matter further if people are interested.

In addition to the two points above, there is also a rather interesting effect on your weight based on your height above sea level, and this, naturally, has no effect on your health, but would have an effect on scales. As many are aware, when astronauts go to space, they often experience ‘weightlessness’. This is because weight varies depending on the gravitational pull you are subjected to, and this is also why you would weigh less on the moon than you do on Earth. What fewer people are aware of is that as you travel further and further from the centre of the Earth, the gravitational pull the Earth exerts on you lessens, and consequently, so does your weight. The effect this has is reasonably small (a decrease of 0.09% of your weight for every 3000 metres up you travel), but if you happen to be climbing a mountain and are taking your scales with you, take account of this! I more decided to add this point in because it’s quite interesting and thought people might like to know. If you’d like to read an article on this matter, please see here.

What factors can effect TDEE?

When you go to a TDEE calculator online, they will generally provide an approximation based on the following factors:

  • Gender.
  • Age.
  • Height.
  • Weight.
  • Activity level.

Some slightly better calculators will also take into account some other factors, such as:

  • Body fat percentage.
  • How often you exercise.
  • How intense your exercise is.

While these calculators are a good starting point, there are far more factors than a calculator can take account of that will effect your TDEE, including (but not limited to):

  • Climate (both cold and warm climates can increase TDEE).
  • Genetic factors.
  • Body composition (whilst body fat percentage is accounted for by calculators, muscle mass generally isn’t).
  • Foods and supplements you consume.

As a result of these factors, it is always best to use an online calculator as an approximation, but then experiment to get a more accurate figure.

How do I work out my TDEE?

To get a very accurate idea of your TDEE, it does take some time. Access to equipment to accurately measure your body fat percentage significantly helps, but I will assume you don’t have access to that. If you do, simply use a measurement of body fat instead of body weight when I mention weight below.

To calculate your TDEE, you should do the following:

  1. Find a reasonably reliable TDEE calculator online, and answer all of the questions as accurately as you can. I personally like the comprehensiveness of this calculator, but be warned that you need to input an email address to get your results, and they add your email to a mailing list and send quite a lot of emails. I’d recommend using a separate email for this site for that reason. Perhaps a better option (thank you to fernly in the comments) is this one. They seem similarly comprehensive (perhaps even moreso) and apparently don’t send emails. Another option (again thanks to fernly) is this one. It is spread out over multiple pages, but it still works well.
  2. Consume as close to that exact figure of Calories as you can for one month, measuring your weight twice daily (once when you wake up and once before going to bed, ideally at the same times each day).
  3. Compare your average weight from the first week of weighing to your average week from the last week of weighing.
  4. If these numbers are very close together, you have successfully found a good approximation of your TDEE, and can use this for future calculations.
  5. If you have lost or gained a fair bit of weight, adjust your Calorie intake accordingly (increasing Calories if you have lost weight, or decreasing Calories if you have gained weight). The extent of this change should be based upon the difference in weight. For every pound gained or lost, change your Calorie intake by approximately 200 Calories per day. Then repeat from step 2 onwards, and continue the cycle until there is no real change in your average weight.

If you would like a spreadsheet template for inputting your data, I have made one which you can find here. To use the sheet, open it, select the ‘file’ dropdown menu, select ‘make a copy’ and name it whatever you wish. You will then be able to edit it as you please. If you don’t have a google account, you can also import a copy to excel by selecting the ‘file’ dropdown menu and then hovering over ‘download as’ and selecting ‘Microsoft Excel (.xlsx)’.

The sheet is set up so an average of all of the weight inputs in a given week is automatically generated as you input data, so all you need to do is put in your weight measurements. The average cell is based upon the number of data points you have input, so if you miss a measurement, just leave it blank and fill in the rest of your data points like normal.

I have my TDEE. What next?

Once you have your TDEE, you can use this to work out how many Calories you should be consuming for whatever it is you want to achieve.

  • If you want to maintain your weight, simply continue consuming this number of Calories. Your weight will still fluctuate slightly, but as a general trend it should remain steady. If it doesn’t, reestablish your TDEE using the method above.
  • If you want to lose weight, the number of Calories you should consume depends on how quickly you want to lose weight. A good Caloric deficit for weight loss is 500 Calories per day, so subtract 500 from your TDEE, and consume this amount. This should lead to a weight loss (that can’t be explained by hydration changes) of approximately 1 pound per week. Bear in mind this is a general trend, and due to natural fluctuations as a result of water weight, you may not notice this initially, so it may be best to continue filling in the spreadsheet I linked above so you can easily see changes in your averageweight over time. A larger Caloric deficit of 1000 Calories per day (TDEE – 1000) is the maximum deficit a lot of people should consider, and it may be too much for some people. If you intend to have a Caloric deficit larger than this, it would be a good idea to go discuss it with your doctor.
  • If you are intending to gain weight, increasing your Caloric intake by the same amounts as someone trying to lose weight would decrease theirs (500 or 1000 respectively) is a good idea. Trying to increase your Caloric intake by too much more, whilst not as potentially dangerous as huge Caloric deficits, may simply be very uncomfortable or even impossible.

If you are intending to specifically lose fat or gain muscle, you also need to take account of your macronutrient ratios. I will go into some detail of this in part 3. Additionally, if you are trying to lose or gain weight, be aware that as TDEE is partially determined by your weight, after some time has passed and you have lost/gained some weight, your progress may well slow or even stop. If this happens, simply recalculate your TDEE and use this new figure instead.

So how does this all relate to ‘lent products?

Knowing your TDEE can be combined with ‘lents very easily to aid your weight loss/gain/maintenance goals. As ‘lents have a set number of Calories per day, it is very easy to weigh out either slightly more or slightly less according to how many Calories you want to consume.

It is important to note that, whilst some micronutrients do indeed scale with Caloric intake, not all do, and those that do don’t necessarily do so linearly. As such, it may be worth supplementing with an occasional multivitamin if you are consuming below 100% of the RDA of a nutrient. Electrolytes aren’t generally included in multivitamins, so if you want to supplement these, lo-salt contains sodium, potassium and chloride, and magnesium is available in many different forms – my personal favourite is magnesium glycinate. There is no need to worry about the extra micronutrients you’ll get from a typical Calorie excess with a ‘lent product, but if you are concerned about this, an easy way to get a lot of extra Calories without affecting your micronutrient intake much is to simply add some light olive oil to your ‘lents. The issue of micronutrients is even easier to avoid if you use DIY soylents, as you can simply raise or lower the ingredients which contribute to your macronutrients (and hence Calories) whilst keeping the levels of your micronutrients the same.