Alex Valentine Personal Training

Effective training for smart people



The best nutritional advice for a healthy body and effective training

Is your FitBit LYING to you?


Or more accurately, your “fitness tracker”? They’re all the rage, and come in so many brands, shapes, sizes, colours…you name it, they sell it! The purpose of them is to track your heart and activity rate, and give you feedback on how active you are, and ultimately give you the answer to the million dollar question…. how many calories you burn.

Sounds amazing right? Strap it on your wrist, hit the gym, and hey presto, you can calculate calories in versus calories out, down to the number of steps you take. For such a small device to give so much information is pretty darn incredible, but just how accurate is it?

A recent study by fancy pants Stamford University found that fitness trackers are amazingly accurate at calculating your heart rate, with as little error as just 2% (Apple Watch). Even the largest heart rate error margin was just 6%, which considering the device goes nowhere near your heart, it’s pretty accurate!

But when it comes to calorie counting, that’s where the margin of error gets a little scary. How accurate would you say a fitness tracker is at counting calories? Maybe 5% error? 10%?


The smallest margin of error for counting calories, was 27%. YES, THE SMALLEST! (On FitBit Surge). You did not read that wrong. So if a fitness tracker says you have burned 2,000 calories that day, it could actually be as little as 1400 calories. The largest margin of error was 92% with the PulseOn. Again if it stated you’d burned 2,300 calories in a day, it could be as low as approximately 1,240 calories (read the full study here: ).

Why is this important? We know that calories consumed versus calories burned are directly related to weight loss. If people eat more calories than the body burns, it results in weight gain. If people are in a moderate calorie deficit (are safely consuming less calories than their body needs), it will result in weight loss. The problem arises when the estimation of how many calories a body burns in a day is inaccurate. An overestimation will result in no weight loss at best, and weight gain in the worst case scenario. Conversely is the estimation is too low, it can result in drastic unsafe weight loss and possibly irreversible hormonal changes (like the 1200 calorie a day diet…don’t get me started on that crap!). The most accurate way to measure calories burned in a day is via an oxygen consumption machine to determine how much oxygen our body needs and calculate our calorie burn from that. Which is really easy because everyone has one of those, right?? OK so not everyone has these, so the next best thing is to calculate your Basal Metabolic Rate. This is the number of calories your body burns at rest. The next step is to multiply this number by the amount of activity you do on a daily basis. You can use this handy link to work it out:

Nothing is 100% accurate, but this calculation is the quickest and most accurate way we can work out how many calories your body needs, which is so important for weight loss. Often when I introduce people to this calculation, I will hear protests of, “but my FitBit says…..”, or, “I treated myself to a take away because my iWatch said I burned xxxx calories on my walk today”. It’s an easy trap to fall into, so make sure you do the calculation yourself so you know for sure.

Despite what you may think, I don’t hate fitness trackers. I even have one myself…..


But hang on I hear you say! You’ve just told me my fitness tracker is LYING, so why would you have one?? I guess it depends what you have one for. I use the heart rate monitor to track the peak heart rate zones I’m training in, so I can tailor the intensity of my workouts depending on what part of my Roller Derby season I’m in. But this function is useful for everyone, and with a maximum of 6% inaccuracy, it’s a good guideline of how hard you’re working in the gym. So if you feel like you’re smashing it, but your heart rate is still at 85, you know to crank it up a notch….. 😉

As always, if you’d like any help or advice on how to improve your training or give your nutrition a kick start, drop me an email at , or text me on 07875465275.

Calorie Confusion!

It’s the New Year, lots of people are making resolutions, so you decide to tone up a bit, maybe lose some weight, and generally get in shape. And the  bombardment of “New Year, New You” advertising is kind of every where! So you head to the gym, eat healthy, and hope to see some results. But they might not be coming as fast at you’d hoped.

So what’s going on? It’s always good to do a combination of cardio and weights at the gym (always check with your GP before starting a new exercise program!), but are you eating to support your goals? A lot of people check the labels on food to make sure they’re eating low fat, low salt foods, and that they’re sticking to the Government Recommended Daily Allowances of calories, kind of like this:

food label

So these are the top ones that people check; energy (calories), carbs, fat and sodium (salt). But this isn’t the whole story. Along with carbs we need to check the figure below that, because not all carbs are equal. This figure shows how much of these carbs are sugars (yup, regular old sugar that people put in their tea!!). Make sure you check this figure on “low fat” or “healthy option” foods, as they often remove fat and replace it with sugar. This can account for lots of excess calories in our diets, so make sure you check food labels thoroughly.

The one that a lot of people don’t check, is how much protein is in their food. People who attend the gym regularly will need at least 1g of protein per kilogram of bodyweight (people with kidney problems or health issues should consult their GP before changing their diet). So make sure you’re eating enough protein to support your goals….protein isn’t just for body builders!

So, here’s the big one that gets us……

calorie conf image

There are sooooo many articles out there advocating different amounts of calories that will give “optimum weightloss”. The 5/2 diet, the 1200 calories diet, the only having liquids diet, the “take these pills and they’ll make you lose weight” diet…. is it any wonder we’re confused??

Calories confusion

So how do we know how many calories to consume to lose weight, or to put on muscle? It’s easy, we use the Basal Metabolic Rate calculator. To make it even easier, here’s a link to one:

This will work out how many calories you need to eat in a day to maintain your body weight and to survive. Believe it or not, it’s usually a lot lower than the Government RDA! There is also a calculation called the Harris Benedict Formula, which will work out how many extra calories you need to eat depending on your activity levels. If you want to lose weight, create a calorie deficit in your diet of NO MORE than 500 calories, either through diet or exercise, or a combination of the two. Any more than this, and the weight loss might not be sustainable or safe. If you do this every day for a week, you’ll burn 3,500 calories a week, which equals weight loss of 1 pound a week. It’s that easy! You can burn 100 calories in 10 minutes if you go for a 10 minute jog. Just 10 minutes you say? Yes! Happy days 🙂

Also give my article “Weights for Weightloss” a read if you’re interested in toning up, losing weight and getting strong. And as ever, if you have any questions or would like a free consultation with me, feel free to email me on

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