TrainingPeaks New ‘Fueling Insights’ Promise to Help You Estimate Your Calorie Burn (but I Have Some Caveats)

Learning to feed well is crucial for endurance athletes – asking me how I use Gu to pass through racing marathons. However, it took a lot of tests and errors (and not a small amount of gastric distress) before understanding how and when to supply the long tracks. I would have loved a kind of guidance throughout my trip, or even raw data on which I could rely for ideas.

From now on, Popular Fitness App Trainingpeaks has launched intriguing power – and potentially misunderstood – which could help serve this goal: to feed ideas. Developed with the physiologist of Dr. Iñigo San Millán, the tool promises to “translate your power meter data into specific carbohydrates and fat burns” during cycling training. It is innovative, scientifically anchored – and likely to be quite misinterpreted by the very athletes that it is designed to help.

Promise and science

During the exercise, your muscles need a lot of fuel. The calories they burn come from two main sources: fats and carbohydrates. Fat is the main source at rest and for a low intensity exercise, but the more hard you work, the more your body is based on carbohydrates in addition to fat. Your body does not have long-term carbohydrates reserves as it does for fats, which is why athletes pay attention to gicularity before races, and make sure to consume carbohydrates (in the form of gels, drinks and sometimes even solid food) for longer walks or races.

The amount of carbohydrates you should eat during these efforts is, of course, linked to the quantity of burns, so obtaining specific estimates can help you understand how to supply. Elite cyclists will do exercise tests in a laboratory to obtain estimates of their personal use of fuel, but most occasional runners and cyclists are doing nothing like this.

The concept of TrainingPeaks is truly convincing: instead of counting on generic calories estimates based on weight and heart rate areas, fueling information from more than 250 laboratory calibrated tests carried out by San Millán using respiratory exchange rate equipment (RER). The system classifies athletes into four metabolic profiles according to the level of performance and sex, then uses power data to estimate carbohydrates in real time and oxidation of fat.

The methodology is healthy in principle. San Millán’s research has revealed coherent models: recreational athletes burn fuel differently from elite cyclists, and these differences are predictable to serve as a basis for reliable models. The higher your output power, the more your body moves to burning carbohydrates instead of fat – a well -established physiological principle that the algorithm tries to quantify in grams per hour.

When Lifehacker’s senior editor -in -chief, Beth Skwarecki, finished a VO2max test, her laboratory data deleted her, revealing when she burned carbohydrates against fat, and how many of each she burned. Her respiratory exchange rate indicated that her body mainly used fat for the few minutes she was walking for a warm -up. When the test increased to jogging, it burned about 2-3 grams of carbohydrates per minute from this point, with carbohydrates being 85% or more of the fuel used and fat by 15% or less. During the last minutes of the test, when things became really intense, the estimates for the use of carbohydrates were more like 3-4 grams per minute.

Trainingpeaks underlines how the work of San Millán with the Riders of the Tour de France has contributed to passing current strategies of supplying high carbohydrates which have become standard in professional cycling. Its laboratory results have directly questioned conventional wisdom and pushed the admission recommendations from 35 to 55 grams per hour to 80 to 125 grams per hour.

What is the use of these data?

Here is where enthusiasm should respond to a good dose of skepticism. Trainingpeaks is essentially extrapolating from laboratory data collected during ramp tests controlled to predict the use of fuel during real training involving variable intensities, environmental conditions and individual metabolic states. It is an important jump to make with confidence.

The company recognizes certain key limitations, but perhaps not well enough in sight. The model presupposes a “nourished state” – which can be less precise for the training on an empty stomach. It is currently in cycling only, because racing power meters do not have the precision and adoption of cycling meters. And above all, the numbers of carbohydrates it produces represent What your muscles oxidizednot what You should consume During the trip.

This last point cannot be overestimated: when the feeding of the information tells you that you have burned 600 grams of carbohydrates for a four -hour walk, this does not mean that you should consume 600 grams of carbohydrates during this walk. Trainingpeaks recommends replacing around 50% of the carbohydrate burn, taking into account existing glycogen reserves and digestive limits. This does not make half a title as flashy, but I hope that the cyclists will grasp the nuance.

Fat burn figures should not be taken as another advice on the amount of fat that should be in your diet. These refueling estimates concern the internal accounting of your body – what calories it draws from there during the exercise – not on the balance of macros in your overall diet.

How data can shape your routines

Trainingpeaks recognizes that its figures could easily be misinterpreted and have built a useful FAQ to solve the problem. However, the explanations seem inadequate for the complexity they introduce into the mixture: the average cyclist by seeing “800g burned” is likely to panic about their refueling deficit or to try to consume impossible quantities of carbohydrates, potentially leading to, well, a gastrointestinal hinge distress.

I would add that the choice to separate users into four metabolic profiles to add another layer of potential confusion. The athletes must select their category, but the distinction between “competitive” and “trained” is not always clear, and being mistaken could considerably distort your recommendations.

Although Fourling Insights is currently limited to cycling, I cross my fingers that technology will also be used to help runners. The same basic principle applies: higher power generally means more oxidation of carbohydrates. However, the measurement of racing power remains less standardized and specifies than cycling power, so the problems of precision abound. In addition, if I know the runners, I know that their supply strategies are individualized and particular.

The bottom line

The science behind the launch of Fourling Insights is exciting. For coaches working with serious athletes, the tool could provide valuable information on training stress and the supply of strategies over time. But athletes and coaches should consider these figures as approximate estimates rather than specific orders. The tool works better when considered as part of a wider supply strategy, and not to replace individual experimentation and common sense.

For the moment, perhaps the most promising use can be a comparative analysis – by following the way in which the supply of requirements changes between different training, the identification of sessions in particular with a high intensity of carbohydrates or the monitoring of trends on a training block. Perhaps certain relative ideas could even prove more precious than absolute numbers.

As with any new sports technology, the wise approach is prudent optimism. Consider ideas, but do not let them replace the years of proven supplies and personal experience. And remember: no algorithm, as sophisticated, can replace the fundamental test and error process to learn what works for you.

Fourting Insights is currently available for Premium Trainingpeaks Users for cycling training with electric meter data.