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Our thoughts on basal metabolic rate and caloric intake.

Jamie was recently asked to wear a heart rate monitor for a full day by the vascular specialist because he wanted to see the fluctuations in his heart rate throughout the day.  We thought these results were really interesting and wanted to share the results to help our clients develop and understanding of Basal Metabolic Rate (BMR: the rate at which the body uses energy while at rest to maintain vital functions such as breathing and keeping warm) and caloric intake.

If your goal is to lose/gain or maintain weight then these results might make you think about your own daily activity and your own input because it certainly opened my eyes and got me thinking.

Jamie wore the heart rate monitor from 7:30am-8pm, in which time he personal trained 8 clients (8 hours) and walked his dog at a slow pace for 20mins.  The rest of the daily he remained relatively sedentary.

His results were as follows:

His peak heart rate was 102bpm

His lowest heart rate was 64bpm

His average heart rate was 81bpm

Jamie’s predicted maximum heart rate is 192bpm, which therefore means that he averaged 42% (81bpm) intensity throughout the day.

Once you add Jamie’s daily activity to his total amount of calories used throughout the day his net calories used was 3221kcal.  This means that if Jamie wants to maintain weight he needs to consume 3221kcal per day.  Now Jamie isn’t exercising at the moment due to having Deep Vein Thrombosis (DVT) but he usually exercises 5 times per week for 60mins, which would push his net calories up even further to around 4000kcal depending on what type of exercise he does and what intensity he works at.

To lose or gain 1lb of fat we need a calorie deficit/surplus of 3500kcal, which divided over 7 days is 500kcal per day.  We agree with the World Health Organisation and also believe that any more than 1lb gain/loss per week is deemed to be achieved via an unhealthy method. Therefore the minimum amount of calories Jamie should be consuming when exercising is 3500kcal and the maximum is 4500 depending on his goal.

Now straight away, the alarm bells are ringing and I have a few questions…

That seems to be a hell of a lot- I thought we were supposed to have 2000kcal per day?

Some of our clients eat 1000kcal per day: how and why are they struggling to lose weight?

Even more so-how are some clients gaining weight?

Now I’m sure there’s a few people reading this article that are saying that Jamie isn’t like you and the average person needs nowhere near the amount of calories he needs. Well I’ll agree that Jamie isn’t your average person.

Our average client is 40-50 year old, who drives an hour to and from work every day and sits at a desk all day long and exercises twice per week.  I worked out that a 52 year old woman who was 5ft 5inches and weighed 72kg has a BMR of 1400kcal per day. But remember that’s without doing anything so she still needs to add her activity to this figure. So that 2000kcal prediction is starting to look about right now.

Most of our client’s daily routine follow something similar to this:

They usually skip breakfast after they get up at 6am because there in a rush to miss the traffic.  Have a working lunch, which is usually a spur of the moment bad choice and then go home tired because they haven’t yet consumed 1000kcal.  Over the next 3-4hours before they head off to bed they will probably consume their remaining 1000kcal because they are starving and tired and the body is craving food and sometimes alcohol to help unwind after a stressful day. This process is then repeated for the next 5 days before the weekend onslaught.

Over the course of a week the average client should consume 2000kcal per day, so 14000kcal per week.  In realty the average client eats 1500kcal for 4 days and 2500kcal for 3 days which equals 13500kcal per week so in theory they should lose 1lb every 7 weeks and now you can see why people turn to diets because that seems like a lot of hard work for no result?

This theory however is not always the case and more often than not people who follow this eating pattern usually put weight on (how is that possible when we have just worked out the math?), which in turn leads to clients thinking that reducing their caloric intake during the week because they aren’t going to be good at weekend are they? This further reduction in calories is actually not helping, in fact its hindering your long term weight loss.  Sure you will lose weight short term because of your reduced calories but what weight have you just lost (its more than likely to be muscle mass) and can you sustain these low levels of caloric intake long term?  Surely you must be deficient in your recommended macronutrients/vitamins and minerals required for your body to stay healthy?

If this sounds like you then maybe your lifestyle needs a complete overhaul but the most obvious change we would advise is to start balancing out your eating over 7 days.  We believe that eating between 1000-1500kcal per day for 4 days is actually resulting in your metabolism slowing and getting used to undereating and when you overconsume over the weekend the body is shocked with excess calories and you can’t burn off this excess.

Now we don’t recommend you start eating 2000kcal overnight if you’re used to eating half of that, you need to steadily increase your daily caloric intake by approximately 15% every two weeks and monitor you weight.  We believe your metabolism will start to increase and you will reduce the risk of losing muscle mass (everybody knows that the more muscle mass you have the more calories you will burn which allow you to eat even more). You can also try to reduce your weekend overconsuming over a period of time until it becomes a habit for you to eat the same amount of calories 7 days a week.

Remember alcohol calories are empty calories so try to limit your alcohol intake where possible.  Now I’m not saying you can’t drink alcohol period just balance your intake with extra activity.

Your body is not like a bank balance-you can’t just overspend all the time and make cutbacks to make up for it.  Consistency is definitely the key to sustained weight.

Jamie was recently asked to wear a heart rate monitor for a full day by the vascular specialist because he wanted to see the fluctuations...

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