Intermittent Fasting Challenge: OMAD Diet

In recent years, intermittent fasting has become very popular. You must have some understanding of the concept of fasting, but you may not fully understand it. Fasting literally means not eating for a period of time, but it’s not that simple. In fact, low-calorie nutritional intake should also be ensured during fasting. But how do we start the journey of fasting? Maybe you have heard a lot of intermittent fasting diet plans such as 16:8 fasting, 5:2 fasting, overnight fasting, alternate-day fasting, and so on. And as one of the most popular ways of fasting, the OMAD diet which means one meal a day is really an extreme practice of intermittent fasting now.

What Exactly is OMAD Diet?

OMAD diet is a form of intermittent fasting that can also be referred to as a 23:1 diet plan, which means that you are fasting for 23 hours and eating within only one hour. With the OMAD diet, you can choose to eat whatever meal you choose with no restrictions inside of your eating window but cannot be consuming any caloric beverages or food outside of your one-hour eating time frame. It sounds like a super unconventional and incredible way, right? But as long as you deeply explore this plan of intermittent fasting, you may find something surprising. Let’s continually look and discover the myth of the OMAD diet!

How OMAD Diet works

In essence, like other types of intermittent fasting, eating a meal a day controls how your body finds and uses “fuel”, that is, the food you’ve consumed. When you eat in a more traditional way (three meals a day), your energy comes mainly from the food you eat. And when you get carbohydrates from these foods, your body breaks them down into sugar. If you have more sugar in your blood than that you need, a chemical called insulin will carry the excess sugar into your fat cells. So, if you don’t eat for a long time, your body will produce less insulin. Since your cells still need energy as fuel, your fat cells will then release energy to compensate at this time.

Benefits of OMAD Diet

Most people are so frightened at the thought of leaving only a meal a day that they don’t dare to try this OMAD diet. Or they may think eating three meals a day is a must-do thing every day, which will make them happy, and it will be a pity if they miss any meal. However, supporters of OMAD and even some health experts claim many benefits of this diet including:

Weight Loss

As is known to us, an energy deficit which can be caused by increasing the number of calories you burn or reducing your calorie intake is a necessary part of losing weight. So, if you conform to the OMAD diet, it’s extremely hard for you to be at a caloric surplus because you’re eating only once a day and are not taking in as many calories as you would if taking three meals every day. Once your calorie intake is decreasing, your weight will naturally drop. Moreover, there is also a study in healthy adults showing that compared with three meals a day, limiting calorie intake to 4 hours in the evening can lead to greater body fat loss.

Blood Sugar Reduction

In a sense, the OMAD diet is linked to blood sugar reduction as you are in the long-time absence of food. Since you only eat one meal a day, your calorie and sugar intake will certainly go down, which can eventually lead to blood sugar reduction. So, insisting on an OMAD fasting on a proper diabetes diet can be a perfect match for those who live with diabetes.

Inflammation Reduction

It is worth noting that OMAD has shared the benefits intermittent fasting brings to the body as a way of it. So OMAD will result in inflammation reduction as well with monocytes, as an important producer of a variety of proinflammatory cytokines, greatly reducing after fasting.

Improved Focus

Who hasn’t spent a drowsy and inefficient afternoon in the office? Who doesn’t feel sleepy after lunch? Not surprisingly, most people will experience such a thing and may be wondering how to deal with it. At this time, OMAD may help you eliminate sleepiness when you are digesting lunch.

The reason is simple: there is no lunch for you! In fact, when you fast during the daytime, a chemical called orexin-A is released by your body, which will make you feel more alert. As a result, your focus and productivity on your work can also be improved.

Possible Side Effects of OMAD Diet

As an old saying goes, “a coin has two sides”. OMAD diet isn’t a magic bullet, and it may also have some possible side effects. And before talking about the risks of OMAD, it is important for those who are pregnant or nursing, under 18, taking insulin to manage diabetes, have a past eating disorder, or take food-dependent medication to know that OMAD is not suitable for them. Besides, the OMAD diet can be strict and psychologically challenging for many people, and whether it works depends on your tolerance and body chemistry. And the following possible risks connect the OMAD diet.

Extreme hunger and binge eating

Compared with three meals one day, eating once a day may force you to stand essential hunger and the bottom line may get out-of-control low. And when you are looking forward to eating the only meal of the day, you may tend to choose some unhealthy food to satisfy your appetite or eat a lot to fill your stomach. This behavior will lead to some health problems and to avoid the occurrence you must enhance your self-control on some unhealthy food with high calories and perseverance on a more balanced diet.

Nutrient deficiencies

As you only eat one meal a day, it can be very difficult to take in enough nutrients from the only meal if the meal fails to be smartly planned, which can negatively affect your health and may bring some unpredictable diseases. So as a practitioner of the OMAD diet, you had better plan a reasonably balanced diet with a combination of meats and vegetables to ensure the necessary nutrients that your body needs.

Slow metabolism

One meal a day can easily reduce your appetite. If you don’t eat enough for a long time, it may reduce your basic metabolism. And the more you limit, the slower your metabolism will run. In the long term, this may lead to unnecessary side effects, even weight gain.

Gastrointestinal discomfort and diarrhea

People who eat one meal a day will find that they restrain themselves during fasting, and then when it’s time to eat, they eat a lot at once. Such a short period of overeating may cause abdominal discomfort, ranging from abdominal distention to severe diarrhea and other adverse reactions.

What to Eat and Avoid in OMAD Diet

Some friends always feel that they can never make it with only one meal a day, mainly because of insufficient nutritional intake. In fact, you can do it by designing a balanced diet plan with enough nutrients to keep your body functioning well. During the OMAD fasting, you are allowed to consume the following food including:

  • Proteins from animals and plants such as chicken, fish, tofu, and eggs
  • Fresh fruit and vegetables providing vitamins and minerals
  • Healthy fat such as sea fish, avocados, and nuts
  • Legumes such as peas, chickpeas, lentils, and black beans
  • dairy and plant-based alternative products

The key nutrients required by OMAD also include various vitamins and minerals.

Good Sources of Vitamin A

  • Cheese
  • Eggs
  • Oily fish
  • Fortified low-fast spreads
  • Milk and yoghurt
  • Liver and liver products (if you’re pregnant you should avoid eating liver or liver products)

Good Sources of Vitamin B Complex

  • Meat, such as chicken and red meat
  • Fish, such as tuna, mackerel, and salmon
  • Shellfish, such as oysters and clams
  • Dark green vegetables, such as spinach and kale
  • Fruits, such as citrus, banana, and watermelon
  • Soy products, such as soy milk and tempeh
  • Yeast and nutritional yeast

Good Sources of Vitamin C

  • Citrus fruit, such as oranges and orange juice
  • Peppers
  • Strawberries
  • Blackcurrants
  • Broccoli
  • Brussels sprouts
  • Potatoes

Good Sources of Vitamin E

  • Wheat germ oil
  • Sunflower, safflower, and soybean oil
  • Almonds
  • Peanuts, peanut butter
  • Pumpkin
  • Mango
  • Avocado

Good Sources of Minerals

  • Nuts and seeds, such as pumpkin seeds
  • Salmon
  • Avocado
  • Kelp
  • Beef
  • Vegetables

In addition to the foods mentioned above that you can eat during OMAD, there are some foods you should avoid, which includes:

  • Fast food
  • Sugary baked goods
  • White bread
  • Sugary cereals
  • Chips
  • Highly processed foods
  • Sugar-sweetened beverages

OMAD vs. Alternate-Day Fasting

When you search for information in the ocean of intermittent fasting, you will find a lot of ways of how to do IF such as alternate-day fasting and OMAD. But are there any similarities or differences between them? Let’s deeply discuss these two types of intermittent fasting.

When it comes to the similarities of those two, it goes without saying that OMAD and alternate-day fasting both provide an answer to how to do intermittent fasting and do help your health to some extent. Additionally, they are both strict diets and may be hard for people to put into practice.

As for the differences, OMAD fasting literally means eating one meal a day while alternate-day fasting suggests eating normally for one day and then fasting on the next day with a specific pattern. They come in different ways, and it depends on your regular schedules and eating habits when you are in the trouble with these two ways.

Do you feel unhappy and even angry when you are worried about what you can eat and when? Then alternate-day fasting may probably fit you more.

Do you want to lose weight in a shorter time and in a comparatively healthy way at the same time? Then OMAD diet is worth trying.

No matter which way you choose, remember to consult your doctor in advance to see if your physical condition is suitable for fasting.

A Classic OMAD Diet Recipe: Cover All Necessary Nutrients with One Meal

Chicken Noodle Salad

omad diet recipe

Level: Super easy

Time: 40 minutes

Serving: 2 servings

Nutritional values (per serving)

  • Net carbs: 45 grams
  • Protein: 30 grams
  • Fat: 10 grams
  • Calories: 404 kcals


  • 70g medium egg noodles
  • 50g frozen soya beans or frozen peas
  • 1 carrot, peeled
  • ½ small red pepper, seeds removed, sliced
  • 75g mangetout, trimmed and halved lengthways
  • 1 cooked boneless, skinless chicken breast (about 125g/4½oz)
  • 4 spring onions, trimmed and finely sliced
  • 1 long red chilli, finely sliced (deseeded if preferred)
  • 15g fresh coriander leaves
  • 10g fresh mint leaves
  • 15g roasted cashew nuts, roughly chopped

For the dressing

  • 3 tbsp water
  • 3 tsp caster sugar
  • ½–1 tsp dried chilli flakes, to taste
  • 4 tsp dark soy sauce
  • 1 tsp toasted sesame oil


  • To make the dressing, place the water, sugar and chilli flakes in a small saucepan over a low heat and warm gently until the sugar is dissolved. Bring to the boil and cook for 30 seconds, stirring. Take off the heat and stir in the soy sauce and sesame oil. Leave to cool.
  • Half-fill a saucepan with water and bring to the boil. Add the noodles and cook for 3–4 minutes, or according to the packet instructions, until tender. Stir occasionally to separate the strands. Add the soya beans or peas to the noodles, stir well and then immediately drain in a colander. Rinse the noodles and beans under cold running water until the mixture is completely cool. Tip into a large mixing bowl.
  • Carefully peel the carrot into long, wide ribbons or cut into long, thin matchsticks. Add the carrot, pepper and mangetout to the noodle salad. Cut the chicken into thin slices and place in the bowl.
  • Pour the dressing into the bowl and toss so everything is well mixed. Add the spring onions, red chilli, fresh herbs and nuts to the bowl and toss lightly before serving.

Bottom Line

  • OMAD diet is a form of intermittent fasting that allows you to eat once a day. And it can bring the benefits that IF also has but may lead to some possible risks as well.
  • If you conform to the OMAD diet, you should choose the foods carefully to eat and try to avoid overeating the unhealthy food.
  • OMAD fasting and alternate-day fasting are two popular ways of intermittent fasting, and they have their own advantages. You can choose one of them according to your lifestyle and you’d better ask your doctor for advice before you start.

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