Gain 10 Pounds In A Week: Is It Possible For Skinny Guys To Gain Weight So Quickly?

Gain 10 pounds in a week

If you’ve been cursed with the skinny gene like I was, then chances are you’ve thought about gaining some weight. And gaining it fast. This post explains how it can be possible to gain 10 pounds in a week.

A person can gain 10lbs of body weight in a week by eating an extreme calorie surplus. A 120lb male would need 7000-8000 daily calories, or a 200% surplus, to gain 10lbs in 1 week. Heavy resistance training can also be done to gain muscle weight as well as fat.

Whilst this would not be considered to be a sensible bulking approach by any means, It’s still possible.

It would be hard work. But possible.

Below, I explain how I would do it as an ex-skinny guy myself.

How I would gain 10lbs in 1 week based on personal experience and scientific research.


I have a B.S/M.S. in biomedical sciences, used to be a skinny person myselfand have 5 years of experience in different bulking methods. But I have not personally tried the exact practices detailed in this content. This content is purely theoretical and based on what I know from scientific research and personal experience. Whilst the concepts would work, they would also be undoubtedly extremely unhealthy.
Please consult a doctor/physician before taking on any extreme weight gain venture.

How Do You Gain Weight?

Weight gain occurs when more calories are consumed than expended. These excess calories are either stored as body fat or used as energy for the muscle-building process. To gain weight successfully, an individual must remain in a consistent state of caloric surplus for extended periods.

Why Do We Gain Weight?

You may also be interested in WebMD’s explanation of the weight gain mechanism.

To put it simply- overconsuming your daily calories is the aim of the game when it comes to gaining weight.

These extra calories, often called surplus calories, follow one of 2 fates:

Stored as fat or used to build muscle.

If you enter a calorie surplus without working out (i.e. leading a sedentary lifestyle), then most of those extra calories will be stored as body fat.

But if you follow an effective resistance training program (i.e. lifting weights) whilst in a calorie surplus, then a lot of the extra energy can be used to build muscle as well as being stored as fat.

In fact, up to 40-70% per pound of body weight gained can come from muscle.

Either way, you end up gaining weight.

But if you want to tip the scales towards muscle gain (rather than fat gain), then you should perform weight training in conjunction with eating surplus calories.

Is It Possible To Gain 10 Pounds In A Week?

Generally speaking, it is possible to gain 10 pounds of body weight in a week. However, the average skinny person would need to consume approximately 7000 to 8000 calories for 7 consecutive days. This is an extremely difficult bulking goal for a beginner to achieve.

Why it is possible to gain 10 pounds in a week if you eat 7000-8000 calories per day.


Whilst gaining 10 pounds of body weight in a week is not theoretically impossible, the likelihood that a beginner will successfully achieve this goal is pretty low.

You would need to eat around 3500 surplus calories per week for every pound of bodyweight you want to gain (both fat and muscle).

This equates to ~35,000 surplus calories per week, or 5000 surplus calories per day, to gain 10 pounds in a week (35,000 cal / 7 days).

And you should also bear in mind, these are excess calories.

You still need to consume your maintenance calories as well.

For a 25-year-old 120lb skinny male who goes to the gym 3 times per week, his maintenance calories would be ~2400 every day.

For a 25-year-old 100lb skinny female who goes to the gym 3 times per week, her maintenance calories would be ~2000 every day.

So you’d need to eat around 7000-8000 total daily calories to gain 10 pounds in a week.

This would vary of course depending on your exact maintenance calories, which in turn is dependent on gender, age, and activity level.

You can find your specific maintenance calories by plugging your metabolic details into TDEE.

You should also note that it’s easier to gain 10lbs of fat than it is to build 10lbs of lean muscle mass.

That’s because gaining 10lbs of fat doesn’t require you to do anything other than eat.

In comparison, building muscle requires you to structure and follow a resistance training program focused on hypertrophy (muscle growth).

Is It Possible To Gain 10lbs Of Muscle In A Week?

It is impossible to gain 10lbs of lean muscle tissue in a week. The average maximum rate of muscle gain is approximately 0.5lbs per week. There are also high and low outliers dependent on age, training history, gender, genetics, and discipline in maintaining a training and diet plan.

Why the Lyle MacDonald Model suggests it is not possible to gain 10 pounds of muscle in a week.

Younger skinny males with no previous training history following an optimized weight gain program will gain muscle most rapidly.

In comparison, females, individuals with training experience, and those who aren’t disciplined in following an effective workout plan will gain muscle the slowest.

But the point remains.

It’s impossible to gain 10 pounds of pure lean muscle in a week.

With that being said, you could combine your calorie surplus with full-body heavy resistance training to create more favorable conditions for muscle growth.

In other words, eat, eat, eat, and perform weight lifting exercises to challenge the entire body.

By doing this, you would still see a lot of fat gains, but muscle gains would also be increased (approximately a 1:25 ratio of muscle:fat).

You should also remember this:

Although you may not be able to gain 10 pounds of lean muscle in a week, 10 pounds of added fat and muscle weight can still be a very positive change.

This is especially true for someone who has been underweight for a long time and looking to generally add some mass onto their body.

The individual would have more “meat” and less bone”, clothes would fit tighter, and there may even be some definition in areas like the arms.

For information on how much muscle you can expect to realistically gain over a longer time frame, you can go to my other post to learn how much lean muscle mass you can build in 24 months.

How To Gain 10lbs Of Fat And Some Muscle Mass In A Week

The average skinny person requires 7000-8000 daily calories combined with heavy resistance training to gain 10lbs of fat and muscle in a week. This equates to roughly a 200% calorie surplus. The resistance training program should be focused on increasing strength and hypertrophy.

Now trust me, eating so many calories is hard.

You should eat as many calorie and nutrient-dense foods as possible. These contain high calories at a low volume, making it easier to pack in as many calories as easily as possible.

Here are some good examples of nutrient-dense foods:

Nutrient-Dense Food ExampleTypical Calories Per 100g
Nuts and seeds580
Confectionery and chocolate500
Sugary fruits80
Fatty cuts of meat300
Oily fish200
Vegetable oils890
Whole grains380

Ideally, your calories should also come from a balanced variety of proteins, healthy fats, and simple/complex carbohydrates (examples in the table above cover all of these macronutrients).

This ensures you get enough vitamins and minerals such as potassium, iron, vitamin C, vitamin D, and omega-3.


Rapid weight gain is not healthy.

But if you’re gonna do it, you may as well do it in the most healthy way possible right?

Regarding you’re weight training program:

Focus on the Big 5 compound exercises (bench press, shoulder press, barbell row, squat, and deadlift).

Do 5 sets of 8-12 reps for each exercise.

Lift slow (count for 2 secs on the upward phase and another 2 secs on the downward phase).

In a regular long-term strength program, it’s commonplace to apply progressive overload (increasing weight over time).

But since you’re on a 1-week weight gain journey, this is not enough time to apply progressive overload.

The best thing you can do is to choose a weight that challenges you for 8-12 reps in each exercise and stick with that weight.

If you’re a beginner, I’d highly recommend using a spotter too since you’ll be shifting huge amounts of weight.

How Many Pounds Is It Possible To Gain In A Week?

Theoretically, there is no upper limit on how much weight someone can gain in a week. However, the limiting factor is how many calories an individual can consume for the week. Most people, especially beginners, will find it difficult to eat more than 4000 calories a day.

Remember- weight gain requires overconsuming calories.

Beginners will usually ease into their calorie surplus. For example, eating 3000 calories per day in week one, then 4000 calories per day in week 2, and so on.

From personal experience and researching other skinny people’s journeys, it’s rare for a beginner to be able to eat more than 6000 calories a day within the first month of their journey to gaining weight.

Therefore we can infer that most people will only see a realistic maximum rate of weight gain at around 7lbs per week (3600 surplus calories per day x 7 = 25,200 surplus calories per week = 7lbs weight gain.)

But gaining more weight is still possible if you can stomach the calories.

You may also be interested in my other post to find out how long it really takes to gain 10lbs of muscle.

Tips To Gain 10 Pounds Faster

Here are some tips which helped to reach my calorie targets:

  • Spread your calories over 4+ meals a day. Increasing your eating frequency allows you to spread your calories throughout the day and minimize the feeling of bloating and feeling full. The more meals the better. Consuming 6 meals at 1200-1300 calories per meal equates to 7000-8000 calories a day.
  • Eat liquid calories. Smoothies and shakes can be made at home using fruits, milk, peanut butter, and oats. You can even add olive oil for more calories (it sounds horrible but trust me you won’t be able to taste it). Liquid calories are easier to consume and are also faster digesting which reduces the amount of time you feel full after a meal.
  • Choose a good weight gainer powder. These will help a lot. A reputable weight gainer protein powder like this Optimum Nutrition Serius Mass packs 1250 calories per serving. Or you can check out my other article for homemade mass gainer recipe ideas.
  • Have a high-calorie meal before bed. I like to eat a high calorie meal or drink a weight gainer shake before bed. Not only does it help me sleep better on a full stomach, but it also means I spend fewer hours of the day feeling bloated.
  • Add calorie-dense toppings to your meals. Dressings, olive oil, sauces, melted cheese, etc are all packed with calories and also make your food taste nicer.
  • Make 2 of your daily meals a pre- and post-workout. These time windows are ideal for turning those calories into muscle and reducing the bloated feeling you get throughout the day.

You can also check out my other guide for 17 essential steps to gaining your first 10 pounds of lean muscle.


I’ve explained how it can be possible to gain 10 pounds of body weight in a week.

If you’re an average skinny person, you would need to consume around 7000-8000 calories per day for a week. Men would be on the higher end of that spectrum, whilst women would be on the lower end.

Ideally, you should get your calories from as many calorie-dense foods as possible, and spread your daily calories to 4+ meals.

Consuming 6x 1200-1300 calorie meals per day would allow you to hit the 7000-8000 calorie daily target.

But as I mentioned before:

Whilst gaining 10lbs in a week is theoretically possible, it will be extremely difficult to eat so many calories. It’s also not recommended since this kind of crash weight gain course is extremely unhealthy.

Will you be trying to gain 10lbs in a week?

Feel free to send me a message if you have any questions! You can find my details on the “contact us” page.

You may also be interested in the downloadable Kalibre Blueprint PDF which details exactly how I gained 40lbs of lean muscle (it’s 100% free!). It details the exact exercises and nutrition (with printable worksheets) I used to go from skinny to ripped!

Thanks for reading guys!

Peace Out,


(Biochemistry BSc, Biomedical Sciences MSc, Ex-Skinny Guy)


I'm Kal (B.S, M.S)- a health & fitness writer and owner of Kalibre Fitness. I love to nerd out on weight training and nutrition. My primary interests are in muscle hypertrophy mechanisms and strength development. You can connect with me in the "Contact Us" section below!

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