How to gain weight healthily for runners

While may of us struggle to lose weight, being underweight can also have huge health repercussions, especially for runners...

How to gain weight healthily for runners

A huge amount has been written about weight loss. This makes sense, after all, a large number of people take up running to help them lose weight. But there are plenty of runners who struggle to put weight on, remaining on the slim side regardless of what they eat.

Those perpetually battling to lose weight tend to have very little sympathy for people struggling to gain weight, but it can be just as frustrating and miserable an experience on the other side of the scales. It can also have a negative impact on your running.

However, if you take a scientific approach and plan your meals and snacks meticulously, you will see the healthy weight gain you are after.

Body mass index

How do you tell if you’re over, under or just the right weight? Generally, a body mass index (BMI) between 18.5 and 24.9 is used to determine whether you are a healthy weight.

‘Runners tend to have a higher muscle mass, therefore it is advisable to measure body fat % to get a true assessment of body composition,’ says Alexis Poole (ANutr, BSc) Registered Associate Nutritionist Nutrition Manager at Spoon Guru

‘If your BMI is under 18.5 then this indicates your weight may be too low and you should speak to your GP. Since muscle mass is usually higher in runners, BMI therefore also tends to be slightly higher than average.’             

The health risks of being underweight

Being underweight comes with its fair share of health risks.

'Endurance runners tend to have a lower bone mineral density (BMD) than those who do weight bearing resistance exercises such as ball or power sports. Having a low BMD can lead to increased risk of fragility fractures, the risk of which can extend into later life,' explains Poole.

The good news is keeping active is beneficial. 'The National Osteoporosis Society recommend doing exercise (including jogging) to help keep bones strong, however they do highlight that excessive exercise and lack of adequate nutrition which results in being underweight, may contribute to bone loss due to hormones altering,' he added.

'After the menopause, women are at greater risk developing of osteoporosis due to a drop in the hormone oestrogen leading to a decrease in bone density. If you are underweight in addition to going through the menopause, you will be putting your bones at an even greater risk.'

Can being underweight impact your running?

Professional athletes tend to be extremely lean, but they also have access to round the clock professional guidance. For the everyday Joe having a low BMI could negatively impact your running.

‘Being underweight could be a sign of an underlying health condition, so it is vital to explore this further with your GP,’ says Poole. ‘Suboptimal weight can contribute to feeling tired, a weakened immune system and fragile bones, as well as nutrient deficiencies, all of which may negatively impact a runner’s performance and even ability to run.

‘Having ruled out any underlying medical conditions with your GP, being underweight as a result of your dietary choices may mean you develop nutritional deficiencies, which in turn will affect your performance or ability to run,’ adds Poole.

What’s the healthiest way to gain weight?

Compared to the average Joe, a runner's energy requirements are likely to be a lot higher. ‘If the calories you consume do not match, or are below the calories burnt, then you will most likely lose weight,’ says Poole.

‘It’s also worth noting that just existing (for example walking, sitting, breathing, sleeping) burns calories,' he adds. 'During your day-to-day life you will burn calories. That is why for the average person in the UK, to maintain weight, men are recommended to consume around 2500 calories per day, and women around 2000 calories per day. If you then expend more energy by going on a long run, you will have to add these additional calories burnt to your daily calorie food requirements.’

Eating the right food is essential for maintaining a healthy weight. ‘If you are underweight as a result of not eating enough, you should make sure you are consuming a healthy, balanced diet,' says Poole.

'This should consist of good sources of protein, whole grains high in fibre and unsaturated fatty acids, as well as enough calories for your height, age and activity levels. You should aim to increase your weight gradually until your weight is at a healthy level. Don’t binge on foods in the hope that you’ll put weight on quickly, this is not safe nor is it healthy.’

Crunch the numbers

If you struggle to put weight on, work out how many extra calories you need to consume per day to hit your weekly weight gain target. As a rough rule of thumb, one pound of weight is gained for every 3500 extra calories you take in on top of what you normally burn. So if you wanted to gain one pound per week, you are looking at around 500 extra calories per day. As athletes we want to gain muscle mass, not store fat, so it’s important to approach this the right way. Two things are crucial:

  • Ensuring you are getting your extra calories from the right types of foods: protein, nutritious whole grains, and good fats.
  • Incorporating strength training (weight lifting, Pilates, etc) into your fitness programme. This will allow your muscles to build mass in response to the increased demand.

Poole recommends all runners include the following two essential nutrients in your diet:

  • Iron: Iron is essential for the production of red blood cells, which carry oxygen around your body. If your muscles don’t get enough oxygen, you will feel tired and won’t be able to perform as well. Good sources of iron include dark green leafy veg, brown rice, nuts and seeds, eggs, meat, fish, tofu, beans, pulses and iron fortified cereals.’
  • Calcium: Calcium is another nutrient runners should be aware of. Calcium is essential for the maintenance of strong and healthy bones. Good sources of calcium include dairy foods, green leafy vegetables (such as broccoli, cabbage, and okra), soya beans, tofu and products made with calcium fortified flour.

Don't skip carbs

Carbohydrates are often hailed as our worst enemy, but carbs are a key ingredient in a healthy diet, especially for runners.

'The liver converts excess carbohydrates into glycogen. Muscle glycogen is a key fuel for runners and is used as the first reserve to provide you with energy during your runs,' explains Poole.

'Only when muscle glycogen is depleted will your body start looking for other stored sources of fuel in the form of fats and proteins, which it will then convert into energy. For this reason, runners should eat enough carbohydrates so that their body is in excess, and therefore will build up muscle glycogen reserves'

'If you are underweight, your body will not store enough carbohydrate that is consumed consumed, instead it will use this pretty rapidly as energy to fuel your day to day activities, adds Poole.

'Not only are carbohydrates essential daily for a runner, they are especially essential as a pre-run nutrient. To ensure there is enough muscle glycogen, runners tend to carbohydrate load i.e. eating a higher amount of carbohydrates leading up to a race. Carbohydrate loading has been shown to increase marathon runners performance since it ensures there is enough energy to prevent fatigue.'

Healthy calorie increase

Here are our top tips for increasing your calorie intake without it becoming a chore to chew: 

  • If you struggle to eat enough calories to meet your daily requirements, focus on foods that are not only healthy, but high in energy. Foods which have a high energy density such as nuts, olive oil and avocado make a great addition to your diet, helping you stay healthy while trying to increase your calories.
  • Eat consistently throughout the day and don’t skip meals.
  • Increase the number of meals you eat per day, up to five or six. For example, you could have two lunches, one early and one late, and add in a bedtime meal.
  • Carry portable snacks around with you to munch on the go, such as nuts, dried fruit or a banana. Banana on toast is a source of carbohydrates, which will help replace the glycogen that you’ve just burnt, and peanut butter is a source of high-calorie monounsaturated fatty acids, keeping up your calorie intake. 
  • Increase portion size at main meals, weigh your pasta and rice to make sure you are eating enough.
  • Choose good fats. Avoid fatty meat and other foods high in saturated fats (such as chips, crisps and biscuits). Instead choose leaner red meat or chicken and add heart-healthy fats, such as avocado, olive oil or nuts.
  • Bump up your meals by adding healthy high-cal additions: flaked almonds, nut butter, some avocado or guacamole on the side, a handful of grated cheese, or a drizzle of olive oil or flaxseed oil will easily boost calories without making you feel too full.
  • Have something to eat immediately after exercise to restock your glycogen stores. Try chocolate milk, crackers with peanut butter or a banana.
  • Drink some extra calories in the form of juice, milk, smoothies or sports drinks. Smoothies made with fresh fruits, greek yogurt, nut butters and oats can help you towards hitting your calorie requirements if you are limited for time, or if you want an additional source of calories between meals.
  • Have an energy gel before exercising.
  • Drink sports drinks during exercise (as well as water).

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