Exactly what and when to eat before and after a workout, according to a dietitian

Should you train fasted and how much protein is too much? Two top dietitians answer your burning sports nutrition questions once and for all 

The London fitness scene is booming, new studios open each month, challenges and transformation programmes encourage us to train every day to see results fast.

Our appetite for exercise has never been so big, turbo charged by the #fitfluencers we see on Instagram, of course. But are you eating enough and at the right times to sustain your training?

We consulted two top registered dietitians – ​sports and eating disorder specialist Renee Mcgregor and consultant dietitian Sophie Medlin – on how to nourish yourself properly while exercising.

Should you train fasted? How much protein is too much? How soon after a workout should you eat? Here, they answer your burning questions...

Should you train fasted in the morning?

This is one of the most debated topics in the fitness world.

It depends on your workout, but...

Renee Mcgregor: In general I’m not a big fan of fasted training. You should definitely not consider it for a morning workout that is high-intensity such as intervals, HIIT, boxing – basically any session where you are working above 8/10. This is because the levels of cortisol, our stress hormone, are highest in the morning, if you then add further stress to the system by training at a high intensity without any fuel, you can cause cortisol to become chronically high which in turn can block the hypothalamus and pituitary gland, impacting the production of sex hormones oestrogen and testosterone, important for a number of functions in the body.

It has been shown repeatedly in scientific studies that it is very difficult to hit and maintain these intense efforts with no fuel, specifically carbohydrate.

If you are someone who insists on this type of training, it is important that it is at low intensity, that is an effort of 6/10 or below and that the session is no more than 60 minutes and no more than twice a week.

Sophie Medlin: Fasted exercise in the morning can work well for some people to achieve fat loss. Taking advantage of your overnight fast means that you’ll be tapping into stored energy in muscles or from fat stores to fuel your work out. For average people, the beneficial effect is likely to be minimal but if you feel good when you exercise in the morning and this works for your routine, then you can make the most of this. For some people, fasted exercise means that they feel lethargic and exercise becomes a huge chore and a burden which may reduce exercise performance and therefore reduce it’s effectiveness. If you have a workout that makes you feel bad and causes you additional stress and discomfort, you will negate the effects of the fast anyway so it is always best to exercise when it fits in with your routine and you feel most energetic.

What are the best foods to eat before a workout?

Renee Mcgregor: Ideally you want to get easily digestible forms of carbohydrate, so good options include banana and fruit yoghurt, oatcakes with mashed banana, fruit loaf or crumpets. This provides the body with carbohydrate effectively and efficiently ensuring there is enough energy going to the working muscles.

Sophie Medlin: Depending on when you last had a meal, you might benefit from a snack before your workout. Some people find that eating too close to a workout causes discomfort or cramps. Most people will find that leaving a gap of 60-90 minutes between eating and training works best. If you need to snack a bit closer to your workout, a snack that won’t sit in your stomach for too long with some fast releasing carbohydrates usually works well. A banana or a smoothie are good options, a yoghurt or a glass of milk would also work.

What and how soon after a workout should you eat?

Renee Mcgregor: Ideally you want to eat as quickly as you can. If you have done an intense workout and your next meal is over 2 hours away or you are training again within a 12 hour window, you want to take on something within 30 minutes.

One of the best options is flavoured milk as this provides easily digestible in the form of lactose and glucose as well as protein to help start repairing the body. If you are going to eat within the hour, then your next meal is the ideal recovery. Aim for a good mix of carbohydrate and protein – eggs on toast; granola and Greek yoghurt, bagel with peanut butter and banana, chicken pasta salad or baked potato with tuna are all great options.

Sophie Medlin: After a workout, most people will want to focus on protein to make sure there is enough of the right amino acids available to build and repair their muscles. We also benefit from having some carbohydrate at this point to aid recovery. If you’re not due to have a balanced meal with a protein source within an hour of your workout, the best thing for muscle growth and repair is the balance of amino acids and carbohydrate from dairy. A yoghurt with some fruit or half a pint of skimmed milk is ideal. Chocolate milk is also well regarded by professional sports coaches as a workout recovery drink. If you’re following a vegan diet or don’t tolerate dairy well, a plant-based protein shake or soya milk would work well. Other plant-based milks are not ideal sources of protein and don’t contain all the necessary amino acids.

How much protein do I need and should you have a protein shake?

Protein is essential for repairing muscles post-workout but it can be confusing to know exactly how much of it your body requires.

According to the British Nutrition Foundation, the protein requirements of a normal adult is 0.75g per kilo of bodyweight per day. For strength and endurance athletes, this increases to around 1.2-1.7g/Kg BW. So if you are working out regularly, your protein requirements may be slightly higher than the average person in order to help repair muscles after exercise. However, it stresses, "most people in the UK consume more than the recommended amount of protein, so increasing your protein intake is generally unnecessary." Check out its table showing the protein content of popular foods here.

Renee Mcgregor: Protein shakes can be useful as a convenient form of nutrition if you are unable to take on recovery in a real form. However not all protein shakes are useful. Always try to find a shake that contains carbs and protein or make your whey shake with cow's milk.

The key is ensuring carbohydrate availability around your training schedule – this is instrumental in ensuring hormonal regulation and yet it is often the nutrient most avoided.

Sophie Medlin: Protein shakes can be a convenient way to recover from and fuel a workout, the problem ;is they are a highly-processed food which is something that most people will want to cut down on.

People who are working out 5-6 times per week or who are competing and focusing on performance will [require more protein], which can be slightly harder to achieve without focusing on having protein at every meal and two high protein snacks per day – this is where convenience foods like protein shakes and protein bars can be useful.