Just by gaining an extra 500 calories a day (which is pretty easy if you follow the instructions below) you can aim to gain between 1lb and 1. 5 lbs per week. However, it is important to be aware that these extra 500 calories should be gained in a healthy way, by eating more calorie-rich foods that are still packed with vitamins and nutrients. Gaining weight by eating more junk food is not a good idea, as it will leave you feeling unwell and sapped of energy, and could lead to further health problems down the line. You might also boost your calorie intake by adding a protein powder to your diet. Protein powders are rich in lean protein and extra calories and can be blended into foods like smoothies, yogurt, hot cereals, and others. You should always consult with your doctor or nutritionist before embarking on a weight gain plan.

Foods containing plant fats should be your first option - this includes items such as nuts, seeds, peanut butter, avocados and olive oil. Spread peanut butter (or almond butter) on toast, eat half an avocado with every meals, eat handfuls of nuts or seeds as a snack and sprinkle olive oil over salads and veggies. You can also gain some healthy fats from animal sources, however these foods also contain saturated fats (the unhealthy kind) so you should only eat in moderation. Foods containing healthy animals fats include lean meats and full fat dairy products - although if you have high cholesterol, you should probably stick to low-fat options.

Good sources of protein include lean meat, fish and poultry, in addition to eggs, whole grains, dairy products and legumes. You should aim to eat about 5 oz of protein per day, from a combination of these sources. You can also increase your protein intake by drinking protein shakes, or adding a protein supplement to juices and smoothies.

Try stir frying your vegetables in a knob of butter, or drizzling a little olive oil over salads and cooked veggies. Simply by adding a tablespoon of these fats to each dish, you could be adding 100 calories! However, it’s important not to go overboard when cooking in fat, as too much can be unhealthy. When possible, gravitate to healthier fats like olive, canola or safflower oil and avoid using unhealthy ones like lard or margarine.

Try drinking a large glass of orange juice in the mornings (along with your normal breakfast), it’s high in calories and is tasty and refreshing too! Consider drinking a glass or two of milk throughout the day - the full fat option is high in calories but will also provide lots of protein and calcium - which is ideal for thinner people who are more prone to lower bone densities. Protein shakes will help you to gain muscle mass, particularly if you’re working out, while tasty milkshakes are perfect for the occasional treat.

Over time, your stomach will adjust to the bigger portion size and you will no longer notice the difference. One good trick to help you with this is to try serving your food on larger plates - this will trick your brain into thinking that you’re eating less than you actually are.

This can help you with your weight gain as you’ll feel less bloated after each meal. Try to get a balance of protein, starch, vegetables and fat with each meal.

Grab a handful of nuts while you’re watching TV, eat a banana on your way to work, or spread some hummus on wholegrain crackers while you’re waiting for dinner.

Therefore, it’s a good idea to make your food more appealing by experimenting with herbs and spices and by making new dishes that you’ve never tried before. You can also improve the flavor of food by adding tasty toppings - like a dollop of full-fat mayonnaise to a turkey sandwich, a sprinkling of cashew nuts over a stir-fry or salad, or a handful of cheese over homemade tacos or spaghetti bolognese.

Eating a little faster than normal can help you to consume more food before you start to feel full, thus increasing your calorie intake. Don’t go too fast though, as this can leave you feeling bloated and sick.

Strength training includes working with weights and performing exercises such as squats, deadlifts, bench presses, bicep curls, crunches, chin-ups and leg curls. If you’ve never done strength training before, it’s a good idea to enlist the help of a personal trainer who can show you how to perform the exercises safely and correctly. Just keep in mind that the more you exercise, the more calories you will need to consume to replace those you lost while working out. This is where protein shakes and bars really come in handy. Luckily, exercising should also increase your appetite.

Although it won’t be easy, quitting is the healthiest option - not only will it increase your appetite but it will improve your overall appearance, not to mention the health of your lungs. If quitting seems too extreme, at least avoid smoking for an hour or two before meals.

Make a note of every calorie you consumed that day and every calorie you burned (to the best of your knowledge). Also write down your weight after each weekly weigh in. See the numbers written down in black and white will help you to figure out what your you’re doing wrong or what you could improve on. It will also help to keep you motivated once you begin to see progress.

You might try relaxation techniques, yoga, or meditation to help you control your stress levels. If it helps, you can join a class. Make time for things that you enjoy, too. Take time to read or watch a movie in the evening. Take a warm bath before bed.

Set small, manageable goals for yourself - like aiming to gain 4 pounds in a month. This will give you something more tangible to work towards. If you set your goals too high, it’s easy to become overwhelmed and feel like giving up.

Bingeing on junk food many seem like the easier option, but your overall health will suffer and you will not be able to maintain the weight in the long run. Remember that you’re not just trying to gain weight - you’re trying to overhaul your entire attitude towards food.