Fats or carbs? What’s fuelling your gym sessions?
For anyone who trains in the gym, protein is non-negotiable because of its role in repairing and building muscle, but opinion remains divided on how to balance our daily calorie intake between fats and carbs.
Overall, a well-balanced diet comprised predominantly of natural whole foods, with supplements used for additional nutritional support, is the best approach to meet our daily macronutrient and energy requirements.
However, eating specifically for energy or improved strength requires slightly different approaches to get the best results. While the core ingredients remain largely the same, the magic lies in how we construct our macronutrient ratios – the combination of proteins, carbohydrates and fats in our diet – and time our meals.
Carbs as fuel
Various high-carbohydrate diets are available to suit specific needs, from the average person to highly active individuals and anyone who trains hard in the gym.
While carbs have gained a bad reputation over the years as people associate them with sugar and weight gain, when you choose natural carb sources, sticking mainly to complex carbohydrates and timing when you include a few simple carbs in your daily eating plan, you feed your body and muscles with the energy needed for optimal performance in the gym.
We need to predominantly eat complex carbs because we metabolise simple carbs very quickly, which spikes insulin to draw circulating glucose from the blood into muscle cells.
However, your body ultimately breaks down all carbs and starches into glucose. This is the body’s primary energy source, and when we eat more than we use, our body stores any excess in fat cells.
If we’re not burning this immediate energy through exercise and activity, the muscle cells become full and we start storing excess glucose in fat calls.
We also experience a rapid drop in blood sugar levels following these intense spikes, which can leave us feeling lethargic and devoid of energy, with a craving for more sugar to experience that ‘surge’ of energy again.
More worryingly, a constant supply of simple carbs continually raises insulin levels. This process becomes less effective over time and can eventually lead to insulin resistance and then type-2 diabetes.
As such, it is best to eat most (if not all) simple carbs before and during exercise and eat mainly complex carbs from natural, whole food sources throughout the remainder of your day. This approach helps to sustain stable energy levels throughout the day by not spiking blood sugar.
According to the dietary reference intakes published by the United States Department of Agriculture (USDA), 45-65% of the calories in our diet should come from carbohydrates. The right percentage for you will depend on your daily activity level and total energy requirements.
Suitable complex carb sources include:
- Rye or low-GI bread
- Sweet potato
- Butternut
- Basmati rice
- Rolled oats
The fat factor
Anyone who trains in the gym also requires an adequate fat intake and should aim to get up to 20% of their calories from healthy fats to produce and maintain anabolic (muscle-building) hormones.
Commonly accepted guidelines recommend keeping your saturated fat intake to 10% or less of your fat-derived daily calorie intake but you should not eliminate this fat source as your body needs it to produce testosterone.
As such, the ideal diet for gym-goers should provide more calories from lean protein and healthy fat sources, with the strategic use of carbohydrates around training sessions, especially high-volume sessions or those targeting larger muscle groups like legs or back.
A study¹ from the University of Connecticut supports this stance, with the study authors stating that strength athletes should “put less emphasis on a very high carbohydrate intake and more emphasis on quality protein and fat consumption”.
In this regard, studies suggest a range of protein intakes that exceed the guidelines of sedentary individuals (0.8 g/kg/day)
For instance, scientists at McMaster University in Canada released a meta-analysis² that reviewed a total of 49 high-quality studies to determine optimal protein intakes. Based on the research, those eating for strength should consume 1.6g of protein per kilogram per day (g/kg/day), with some studies showing benefits with intakes up to 2.2g/kg/day.
Sources of healthy fats include:
- Salmon
- Nuts (particularly walnuts)
- Seeds
- Avocados
Structuring your diet
When it comes to the carbs versus fats debate, there is no either-or answer. Rather, aim to eat protein at every meal throughout the day, consuming most of your daily carbohydrates before and directly after exercise together with protein. Combine protein and fat at the other meals throughout the day for optimal muscle-building and strength benefits.
For the best results, it is best to consult with a qualified nutritional advisor or dietitian. These professionals will devise an individualised eating plan to ensure you consume the optimal amount of protein, carbohydrates and fats to meet your specific dietary requirements based on your genes, activity levels and specific goals.
References:
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- Volek JS, Forsythe CE, Kraemer WJ. Nutritional aspects of women strength athletes. Br J Sports Med. 2006 Sep;40(9):742-8. doi: 10.1136/bjsm.2004.016709. Epub 2006 Jul 19. PMID: 16855068; PMCID: PMC2564387.
- Stokes T, Hector AJ, Morton RW, McGlory C, Phillips SM. Recent Perspectives Regarding the Role of Dietary Protein for the Promotion of Muscle Hypertrophy with Resistance Exercise Training. Nutrients. 2018 Feb 7;10(2):180. doi: 10.3390/nu10020180. PMID: 29414855; PMCID: PMC5852756.