Over the past month I have used Supersapiens continuous glucose monitor to learn what happens to my blood glucose levels so I can better advise my athletes using it. While running a busy sports nutrition clinic, I train an average 14h of cycling, 300km a week. Here’s what I learned and the nutrition tips I recommend for anyone starting to use Supersapiens.

I was first introduced to Supersapiens by one of my amateur clients last year and since more of my professional athletes are using it in training and racing (when allowed) it peaked my interest to learn more.

Especially after recording my Podcast chat with Till Schenk about how he used Supersapiens during his Stupid 7 Everestings, it was time to learn more and see how my lifestyle, diet and training influence my blood glucose levels.

My blood glucose has gone up, that must mean I shouldn’t eat carbohydrates or this food isn’t good for me?

Before we begin, let me give you a whirlwind biology lesson about carbohydrates, blood glucose levels and insulin.

When we eat carbohydrate, it gets broken down into glucose (sugar) which is released into the bloodstream. Some foods are broken down really fast which makes blood glucose levels spike, while others are digested at a slower pace so you get more steady increases. When blood glucose levels get high, insulin is released to bring it back down to normal ranges - which vary from person to person.

What are normal blood glucose levels?

For the majority of healthy people, normal blood glucose levels can range:

Between 4.0 to 5.4 mmol/L (72 to 99 mg/dL) when fasting
Up to 7.8 mmol/L (140 mg/dL) 2 hours after eating

It’s important to remember that your glucose levels WILL go outside of these ranges at some point. That is totally normal and not something to stress about.

Also, when you are training, the numbers you see are and should be higher than when you are resting.

Your blood glucose levels will be affected by many, many things including:

The amount of food you eat
What food you are eating
Whether there is protein, fats of fibre as well as carbohydrate or sugar
The frequency that you eat
The glycemic index of the food
How processed the food is
If you are stressed
How well you have slept
How active you are
Exercise intensity and duration

And that’s just a start! When there are so many factors to consider it’s no wonder I’ve seen clients get a bit confused or overwhelmed at their Supersapiens data and wonder what to do with it!

Blood glucose fluctuates daily

What my every day blood glucose levels look like on a typical day

What did a sports dietitian learn training with Supersapiens for a month?

So, what did I learn and what are my nutrition tips for anyone thinking about using Supersapiens continuous glucose monitoring?

Don't change your normal diet or exercise habits for the first week using Supersapiens

The temptation will be to change everything straight away, but it is incredibly helpful to have a baseline to work from for what is ‘normal’ habits and practice for you - be it training, food habits, stress levels.

When I was speaking with Till on the Podcast he mentioned that he found using the Supersapiens could work as a bit of an accountability honesty box when reaching for ‘sometimes’ foods. You can’t ignore the facts or live in ignorant bliss of what happens if you see it happening in real time.

I found this helped me become aware of and change some of my unnecessary snacking patterns as I’ll explain below.

Record your diet, sleep, training and lifestyle factors

This is all about helping you raise awareness about what is happening when so you can make sense of the data and put it into context.

While what you eat is going to make the biggest impact on your blood glucose levels, lifestyle factors such as stress also play a big role.

I certainly saw my blood glucose levels spiking and behaving much more erratically on days when I was particularly stressed or not sleeping well.

You want to be specific with your food diary as well. If you can, it may help to weigh foods out so you know more exact portions and can then reflect on what happened when testing alternatives.

Separating out what your blood glucose levels do in every day life versus training is also important. When you exercise your levels will be elevated more than they are when resting or working. Which means that if you train for say 2-4 hours a day, those higher values are raising your daily averages and making them look a bit higher than they may actually be.

Make a plan about what things you want to test

Are you wanting to see what happens if you fuel better in training? Are you trying to reduce spikes in glucose levels in every day life?

You want to be specific about what you want to test so you can learn what happens if you change things up and help you avoid overwhelm.

Test specific foods/amounts in similar situations

Say you currently rarely eat in your training sessions and have seen how your blood glucose levels are low as a result.

If you want to start fuelling your training better and see what a difference it makes, you could take 2 or 3 training sessions that are the same duration, and intensity, do one without any food (that’s your normal control), a second eating 30-40g of carbohydrate an hour (maybe a rice cake or a gel) and another with 60g of carbohydrate.

You then want to look at a) what are my blood glucose levels doing in those different situations b) How does my power/speed/pace differ in those sessions?

Timing makes a big difference!

I ate a cookie 15 minutes before a ride and my blood glucose levels shot up then dropped. In this session I was experimenting with timing of food during 20 minute hill reps to see whether it was better to fuel before each rep, or on the descent.

What kind of things can you test with Supersapiens?

There are SO MANY things that you can test. I had a lot of fun experimenting with different foods, seeing how I responded to different amounts or types of foods or in different situations.

For example, one day while I was getting ready to go for a ride, I ate a small chocolate chip cookie. Eating it before a ride when I wasn’t exercising sent my glucose shooting for the sky, whereas when I ate one mid ride it stayed constant as my body was absorbing it and using it straight away.

This is one of the reasons why I often say to my clients if you’re going to eat cake, biscuits or haribo - eat it on the bike when your body uses the energy!

I tested loads of things out, like what happened if I ate a bag of haribo, or a whole pack of chips or ice cream on and off the bike.

OK so maybe I didn’t eat the ice cream on the bike.. but you get my point right?!

The same food eaten in a different context or with more fat and protein present can respond completely differently, which is fascinating to see in real time.

How is using Supersapiens beneficial to athletes?

I think one of the great things Supersapiens allows, is that athletes can physically SEE the benefit of fuelling more optimally in training.

Too often I see athletes wanting to cut out food from their training to create energy deficits and lose weight faster. With the Supersapiens data you can see how not eating has a negative influence on your performance and physically see how your power or speed is dropping as your blood glucose levels get low.

When the athletes I work with do start fuelling their training better they ALWAYS talk about it being a game changer to their performance. But it often takes months of convincing to start doing this consistently. Maybe this would help convince them faster?!

On the opposite side of the spectrum, if you find yourself snacking mindlessly in the evening or reaching for more sugary energy dense foods, I think the Supersapiens data can be useful to actually show you how it sends blood glucose into a tail spin and help encourage you to swap for more nutritious sustainable choices.

There’s always room for improvement

It’s not about being perfect, but there’s always room for improvement when it comes to our nutrition. Even for me as a sports dietitian!

One of the habits that Supersapiens helped me conquer was grabbing a handful of dried fruit from the jar when I got home from work. I wasn’t hungry, I didn’t really NEED it at that point of time. I was just eating it, mindlessly.

When I discovered that that small handful of dried papaya was sending my blood glucose levels up to 200 then crashing back down minutes later it made me realise that perhaps it was something for me to work on. And I say minutes, because I saw the spike begin within 3 minutes!

Eating the same dried fruit in a ride instead had no effect, again because that energy was being used to sustain the training I was doing.

The effect of dried Papaya when not exercising…

Challenges using Supersapiens

I can forsee the data being quite overwhelming to some people making them afraid to eat foods containing carbohydrates. As I mentioned before, it’s important to recognise that your blood glucose levels will naturally increase and fall with food intake - this is not something to be afraid of!

The sensor is able to hold 8 hours worth of data at a time and currently requires the app on your iPhone to collect and store it. If you don’t log into the app or have your phone handy its pretty easy to lose an hour or two of data.

I have periods where I don’t check my phone for hours, so most days (and especially nights) I typically would lose between 1-4h of data. It’s not really an issue but worth being aware as the daily/weekly/monthly summaries might be impacted!

Speaking of averages, it’s also worth being aware that if you train regularly, your average blood glucose levels may appear to be high - purely because those averages are also including the times when you are training when your body is using large amounts of glucose as fuel.

Exercise intensity = higher blood glucose levels

4h low-mod intensity ride to the coast and back with a lunch stop in the middle. Notice how glucose levels rise during the ride as I climb and expend more energy.

My overall nutrition advice using Supersapiens

I think you realistically need a month or two of data (at least) to start getting your head around how your body uses carbohydrate and what is best for you. Like I do when I start working with new clients, I suggest clearly tracking your food, sleep, stress levels so you can reflect on what you have changed.

Definitely have a few days (preferably a week) of data eating your habitual diet so you can look at what you are currently doing. The temptation will be to start making changes instantly. Resist!. Stick to your normal eating habits and then reflect on how that makes your body react so you can see where there is room to improve - whether that be the timing, amounts, frequency.

When you start using Supersapiens :

Don't change your normal diet or exercise habits for the first week
Record your diet, sleep and lifestyle factors to put your blood glucose levels in context
Make a plan about what things you want to test
Test specific foods/amounts in similar situations

Good luck and have fun!

Gemma

Supersapiens nutrition tips: What I learned from a month continuous glucose monitoring as a sports dietitian