Going for a workout? What you should know about eating before and after exercise

Your stomach is growling en route to the gym. You’re beginning to regret not packing a protein bar or shake in your bag. But wait, you spot the golden arches. Further down, a bakery is selling its last few pork floss buns at half the price. Should you get them?

And what about the time when you exited the gym at 10pm – and you’re not sure whether you want your bed or a burrito bowl?

Ah, decisions, decisions. But these are scenarios that you might have dealt with before. You want to make the most of your efforts in the gym and what you eat can make or break your gains in the long run.

So, what can you grab from the food court, hawker centre, supermarket or even vending machine when you’re not a fan of bars, shakes or smoothies? Should you be noshing at all before breaking a sweat? Here’s a look at some common questions you may have.

Disclaimer: If you have a chronic metabolic condition such as diabetes, see your dietitian for more customised suggestions.

DO YOU ALWAYS NEED A PRE-EXERCISE SNACK?

Not always. If you’re exercising for less than 60 minutes – and you’re not doing an intense workout like HIIT, fast running or high-volume weight training (more than 10 reps per muscle group), a pre-workout snack may not be necessary, said Nicholas Ling, a dietitian from Tan Tock Seng Hospital.

“Studies have shown no meaningful differences in performance,” he said. “This is because shorter duration exercises mainly utilise muscle glycogen stores as fuel. These muscle glycogen stores are built up through your normal main meals throughout the day and will be used during your workout.”

HOW CLOSE TO WORKING OUT SHOULD YOU EAT?

Typically, between 30 and 60 minutes before a workout, said Joan Liew, a professional bodybuilder and sports nutritionist from Fitness Factory. “This window allows the body to digest and absorb the nutrients needed to enhance performance while avoiding gastrointestinal discomfort.”

What can affect this window is the nutritional make-up of your nosh. For instance, “food that has more complex carbohydrates, fat and fibre typically takes longer to digest”, said Tung Yee Nei, the lead nutritionist from Ventrickle, a recently launched Singapore-based nutrition app and food calculator.

As a rule of thumb, Tung suggested waiting the following durations after your last bite:

• Strength and weightlifting: 30 to 60 minutes
• HIIT or sprinting: 30 minutes
• Endurance training: 60 to 90 minutes

If you’re pressed for time, go for fast-digesting carbs such as a banana or a sports drink/gel 15 to 30 minutes before starting your workout, suggested Tung and Ling. Alternatively, sip a sports drink during your workout, said Ling.

“It’s important to remember that theoretical optimal is not quite real-world optimal, so learning what your body responds to is key,” added Tung.

CAN YOU INCREASE YOUR CALORIC BURN IF YOU SKIP LUNCH OR DINNER?

You might burn more fat but it comes at a price. Performing low-to-medium intensity exercises (such as dancing, swimming at a leisurely pace or lifting lighter weights) on an empty stomach might indeed be able to get your body to burn more fat, said Ling.

This is because your reserves of glycogen are more depleted and your body has to tap on fat as an alternative source of fuel, he explained. And the longer your workout duration, the more fat your body burns.

The downside? The fat torching “only persists during the workout and does not increase post-workout fat burning”, said Ling.

Furthermore, “there is no clear evidence that training while fasted will yield more fat loss than traditional calorie restriction”, said Ling. If weight loss is your goal, you are better off maintaining a consistent daily calorie deficit and at least 150 to 300 minutes of moderate-intensity aerobic activity per week, he said.

Liew added that “while working out fasted is an option, especially for low-intensity sessions, having even a small intake of nutrients can enhance performance, prevent muscle breakdown and maintain energy levels”.

Also, you don't want to feel lousy. “Skipping a meal before exercise may lead to low blood sugar levels, causing fatigue, dizziness and decreased performance,” cautioned Liew.

WHAT IF YOU DON’T HAVE MUCH OF AN APPETITE IN THE MORNING?

A few bites of banana will do for that energy boost in the morning, said Liew. Or try these other light, digestion-friendly choices from her:

Liquids:

• Protein shake with skim milk
• A banana blended with milk or yoghurt
• Electrolyte drink with branched chain amino acids
• Small black coffee or matcha

Light, solid foods:

• A spoonful of peanut butter or Greek yoghurt 
• A few rice crackers
• A slice of toast with honey

Or skip the early morning nosh altogether, Ling suggested, provided you don’t feel “abnormally tired during your workout”. “This is because your muscles still have stored glycogen from yesterday’s meals to fuel your workout.”

WHAT SHOULD YOU FOCUS ON: PROTEIN OR CARBOHYDRATES?

It depends. Carbohydrates are crucial for sustained performance, particularly in endurance and high-intensity activities, said Liew.

On the other hand, “a small amount of protein before exercise may help reduce muscle protein breakdown, particularly in resistance training”, she said.

If you’re tempted to grab some fries or curry puff before stepping into the changing room, don’t. “Eating too close to exercising can lead to digestive discomfort, especially with high-fat or high-fibre foods,” said Liew.

WHAT’S A GOOD PRE-WORKOUT SNACK TO HAVE?

We’ve combined the recommendations from the experts for the list below.

Hawker centre, food court or coffee shop:

• Pau
• 1 fishball stick
• 2 chee cheong fun rolls with soy sauce, omit oil
• Steamed yam cake without fried shallots
• Sweet potato porridge

Supermarket:

• Milk or protein shake
• Small tub flavoured Greek yogurt
• Banana or other fresh fruit
• Sushi, 3-5 pieces, avoid mayo-based ones
• Onigiri, avoid mayo-based ones
• Tuna or chicken sandwich with wholegrain bread

Cafe:

• Fruit smoothie with Greek yoghurt
• Oatmeal with fruit or honey
• Plain bagel
• Wholegrain toast with peanut butter
• Grilled chicken or turkey sandwich with wholegrain bread; avoid cheese and mayo

Bakery: 

• 2 slices raisin bread
• Tuna bun
• Peanut min jiang kueh

Vending machine:

• Milk or soy milk
• Almond pack
• Wholegrain crackers
• Nut-based protein bar

HOW SOON SHOULD YOU EAT AFTER EXERCISE?

Ideally, within 30 to 90 minutes, said Tung. “This ‘anabolic window’ (tissue-building and repairing state) was traditionally thought to be critical for muscle growth.” However, research showed that the window can vary, she said.

“If you had a pre-workout meal within one to two hours before training, the anabolic window is much wider, up to several hours,” Tung explained. But if you exercised with an empty stomach, she said, eat as soon as possible post-workout.

Ling, on the other hand, said that eating within two hours after exercise is okay. “Taking a snack or meal within two hours after the workout allows the body to shift from a catabolic state (the breaking down of your body’s tissues for energy) to a more anabolic state.”

He recommended a meal with carbohydrates, lean protein and fibre. “Carbohydrates help replenish glycogen stores, while protein helps kickstart new muscle protein synthesis and repair damaged muscle cells. Fibre helps ward off chronic diseases. This prepares your body for the next session and helps reduce soreness.”

Again, it depends on your type of workout. “If you have just done low-intensity exercises such as Zumba, Pilates or yoga, there is no need to worry about post-workout recovery,” said Liew.

SHOULD YOU SKIP FOOD WHEN IT’S CLOSE TO BEDTIME?

Skipping food isn’t ideal, especially after resistance training, said Tung. “Your muscles need protein to repair and skipping food can lead to muscle breakdown and slower recovery.”

From studies, Tung said the key is to eat a smaller portion and choose a nutrient-dense food with single macronutrients that is less than 200 calories. Consuming 30g to 40g of casein protein after resistance training and 30 minutes before sleep, she said, has been found to stimulate overnight muscle protein synthesis in studies.

But what if you have gastric reflux that gives you heartburn when you eat too close to bedtime? If possible, schedule two to three hours between your last bite of the day and bedtime, said Ling.

“Eat your post-exercise snack as soon as your workout ends to allow as much time as possible for the food to be digested while on your journey home,” he suggested. “If you don’t have those two to three hours, minimise reflux symptoms by having a small snack that has carbohydrates, lean protein and is low in fat.”

WHAT CAN YOU EAT AFTER TRAINING?

Here’s a list of food suggestions from the experts:

Food court, hawker centre or coffeeshop

• Grilled fish with baked potato and steamed or boiled vegetables
• Chicken chop (remove skin) with side orders of mashed potato or rice and garden vegetables or corn
• Fishball or prawn noodles
• Korean tofu stew with rice
• Japanese bento set with saba, rice and miso soup
• Economy rice or nasi padang with 1 or 2 portions of steamed meat or fish, 1 portion vegetables and rice

Supermarket

• Protein shake
• Milk with large banana
• Chocolate milk with fistful wholegrain cereal  
• Ready-to-eat chicken breast or canned tuna with 3 slices wholegrain bread and apple
• Sushi, 8-12 bite-sized pieces, avoid mayo-based ones
• Japanese rice bowl, avoid mayo-based ones

Cafe

• Egg-white wrap
• Baked fish tacos with salad
• Salmon poke bowl
• Grilled chicken dish with baked potato and roasted vegetables
• Roast chicken and pasta

Bakery

• Red bean bun
• 1/2 bagel with smoked salmon and cream cheese
• Turkey, chicken or egg sandwich with wholegrain bread, avoid mayo-based ones
• Chicken or tuna pie

Vending machine

• Soy milk with biscuits
• Unflavoured milk with baked nuts and fruit chips
• Rice crackers and whole or pre-cut fruit
• Chicken, ham, egg or beef sandwich with wholegrain bread, avoid mayo-based ones
• Ready-to-eat meal such as spaghetti bolognese or black pepper beef with rice