Protein is ‘King’ when it comes to growth and development providing the building blocks of amino acids needed for muscle mass and tissue repair. But it is carbohydrate that fuels this body building process.
Yet there are people who fear carbohydrate, concerned it will ‘increase their weight’ and ‘make them fat ’and let’s be honest, it can.
Too much of any of the macronutrients Protein- Fat and Carbohydrate will.
The secret is getting the right balance.
Finding balance
For good health and weight management ideally, protein should make up between 15-20%; fat 25-30% and carbohydrate 50-55% of our daily energy/calorie intake. With the overall calorie needs being dependent on our weight goals, age, gender and activity
If our overall available energy levels fall below that which we need for daily living, body functions and exercise (creating an energy deficiency) this can lead to a cascade of physiological decline in our mental and physical health and performance.1 For athletes in training this condition is known as RED-S. ie. Relative energy deficiency in sport 2 which can derail even the most committed athletes performance (See more articles below)
If combined, a low carbohydrate level if accompanied by an overall energy deficiency can lead to low muscle glycogen levels. In the case of an athlete, this could then go on to impair their anaerobic output during high-intensity sprints and time to exhaustion tests.3 It can also lead to hormone disturbance4 and ill health.
Hormonal changes seen with low carbohydrate diets
Here are some key examples of hormonal changes that may occur as carbohydrate levels fall
- Elevated levels of cortisol (the stress hormone) suppressing the immune system.
- Reduced insulin levels increasing hunger and fatigue.
- Reduced reproductive sex steroid hormones such as Testosterone in males; Progesterone and Oestogen in females.
- Increase in Ghrelin and reduction in Leptin leading to increased appetite.
- A drop in training adaption reducing performance and health
The Quality of Carbohydrates Matter
Carbohydrates in the form of fresh fruit and vegetables, breads and cereals are a good source of low GI carbohydrate, dietary fibre, vitamin C and B group vitamins and antioxidants, plus plant proteins and are important for good health.
While all vegetables are good for us some are very low in carbohydrate and energy. For instance, green leafy vegetables such as kale, spinach, cabbage, lettuce also tomato, cucumber, carrots, radishes, courgettes etc. So,if you are needing to gain muscle mass or are very physically active, then try to also choose vegetables and foods that have more starch such as potato, wholegrain bread and cereals, brown rice.5
Your dietitian can show you how to gear your carbohydrate intake /levels to suit your changing levels of exercise. Greatly reducing levels of fatigue and improving performance.
At the other end of the scale sits high GI carbohydrates such as white bread and white pasta, lollies, sugar sweetened soft drinks, cakes and biscuits which are less healthy because they usually contain more refined sugar and saturated and trans fats. Even very active athletes need to take care when eating some of these foods.
Examples of how low carbohydrates can slow body building and repair
Active ageing athlete
John* was an over 65-year-old, very active, lean gentleman, training every weekday at the gym for 90 minutes but mentioned feeling tired and had recently sustained a nasty fall on the road. John, while not a patient, asked me how to speed the healing of his badly scrapped elbow?
When I enquired about his diet, he would eat a late breakfast of fruit, cereal and yoghurt, but skip lunch commenting “bread and potatoes are fattening aren’t they?” John had milk for afternoon tea and a dinner of lean meat or fish and salad at night.
With no lunch, John’s protein intake was only meeting 2/3rds of his needs and his carbohydrate intake was insufficient to match his needs for training. John needs to take care not to lose too much weight, especially muscle mass with age.
Fit young athlete seeking weight gain
Nick* was a fit 19 -year-old keen to build up his muscle mass for rugby and wanting to gain 7 kgs. After a GP clearance and cholesterol check, Nick was shown a system of carbohydrate portion control and how to gear this up and down according to his time spent in training and competition. His protein level was perfect, his fat levels kept low as there was a family history of heart disease. John did well gaining 4.5kg within a 6-8 week period then his progress seemed to stall.
A quick assessment showed that Nick was eating sufficient protein and carbohydrate for daily living but not enough of the recommended portions of carbohydrate for training. He needed to change his choice of carbohydrate to include more cereals and starchy vegetables and to undertake some resistance training.
Whether trying to gain or lose weight learning how to manage, not cut your carbohydrate intake, will deliver more available energy at the times when you are needing it the most while also maintaining the integrity of your body’s health and fitness.
*Not their real name
More articles by Lea on this subject
6 reasons to control, not cut your carbohydrate intake
Are you energy deficient?
Potatoes they’re maybe healthier than you think
6 tips to help athletes eat more plant foods
Are you eating enough to build strength
How to stay an athlete and enjoy active aging
References:
- Stening, L.B. How to grow an athlete: From Playground to Podium. 2022 Quentin Wilson Publishing
- Ibid
- Margolis, L.M. et al. Low carbohydrate availability impairs hypertrophy and anaerobic performance. Current opinion in clinical nutrition and Metabolic Care 26(4) 347-352. July 2023
- Williamson C. A bad situation made worse: low carbohydrate intake amplifies low energy availability hormonal disturbances.
- Good sources of starchy foods nidirect.govt.uk
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