Look, let’s be honest. Most people are trying to lose weight, so when you start asking how do i get fat quickly, you usually get met with blank stares or bad advice to "just eat a donut." It's frustrating. You’re likely tired of being the "skinny one" or you’ve lost weight due to stress or illness and you need to fill back out. But there is a massive difference between gaining healthy adipose tissue and muscle versus just becoming lethargic and bloated.
Gaining weight fast isn't actually about eating junk.
If you just smash fast food, you’ll feel like garbage. Your skin might break out. Your energy will plummet. To actually move the needle on the scale in a way that sticks, you need a surplus. A big one.
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The Math of the Surplus
Your body burns a specific amount of energy just by existing. This is your Basal Metabolic Rate (BMR). To get "fat" or gain weight, you have to outpace that number plus your daily activity. It sounds simple. It’s actually quite hard for "hardgainers."
To gain about one pound of body mass, you generally need a surplus of roughly 3,500 calories. If you want to see the scale move by the end of the week, you’re looking at adding 500 to 1,000 calories above your maintenance level every single day. Most people think they eat a lot. They usually don't. When they actually track their intake using something like Cronometer or MyFitnessPal, they realize they’re barely hitting 2,000 calories.
You need to aim for calorie density.
Think about it this way: a giant bowl of salad might fill your stomach, but it has the caloric energy of a AA battery. A handful of macadamia nuts? That’s a literal power plant.
Liquids are Your Secret Weapon
The biggest hurdle to gaining weight is satiety. Your brain tells you you’re full. You have to bypass that.
One of the most effective ways to answer the question of how do i get fat quickly is to stop chewing so much of your food. Liquid calories don't trigger the same "I'm full" signals in the brain as solid food does. A study published in the American Journal of Clinical Nutrition has shown that liquid carbohydrates are less satiating than solid ones.
Build a "Weight Gain Shake" that actually tastes good.
- Two cups of full-fat Greek yogurt.
- A massive scoop of peanut butter (the natural kind, though the sugary stuff works for raw calories).
- A cup of oats (blend them into flour first).
- Two tablespoons of olive oil. Yes, olive oil. You won't taste it, but it’s an instant 240 calories of healthy fats.
- Frozen fruit for flavor.
Drink that before bed. Why? Because if you drink it in the morning, you might not be hungry for lunch. If you drink it at night, it’s an "extra" 1,000 calories that your body can process while you sleep.
Stop Moving So Much (Seriously)
This sounds like terrible health advice, but if the goal is rapid weight gain, you have to look at your "NEAT." This stands for Non-Exercise Activity Thermogenesis. It’s the calories you burn fidgeting, walking to the mailbox, or standing while you work.
If you are a naturally high-energy person, you are burning off your surplus before it can be stored.
Relax.
Take the elevator. Sit down when you can. This isn't about being lazy forever; it's about a temporary physiological shift. If you’re also hitting the gym, keep your workouts short and heavy. Long cardio sessions are the enemy of quick weight gain. They burn exactly what you’re trying to save. Stick to compound movements—squats, deadlifts, presses—that signal your body to use those extra calories for muscle repair and mass rather than just burning them off as heat.
The Role of Fats vs. Carbs
Fat is the most calorie-dense macronutrient. It has 9 calories per gram, while carbs and protein only have 4. If you want to get big fast, you need to lean into fats.
However, don't ignore insulin.
Insulin is your body’s primary storage hormone. When you eat carbohydrates, your blood sugar rises, and insulin is released to shuttle that glucose into your cells. If your cells are full, that energy gets stored as fat. By combining high-fat foods with high-glycemic carbohydrates (think white rice with avocado and fatty beef), you create the perfect hormonal environment for storage.
Is it "healthy" in the long run? Maybe not. But it is the fastest way to gain mass.
Specific Foods to Buy Right Now
- Animal Fats: Ribeye steak, chicken thighs with the skin on, and full-fat dairy.
- Dried Fruit: You can eat 10 dried apricots in the time it takes to eat one fresh apple. The calorie density is five times higher because the water is gone.
- Nut Butters: Keep a jar at your desk. Two tablespoons is 200 calories. Do that four times a day and you've added 800 calories without even sitting down for a meal.
- Rice: It’s easy on the stomach. You can eat huge quantities of it without feeling "blocked up" like you might with whole-wheat pasta.
Dealing with the "Hardgainer" Myth
A lot of people say, "I have a fast metabolism, I can't gain weight."
While metabolic variances exist—some people genuinely have a higher "uncoupling protein" count that makes them burn energy as heat—most of the time, it’s a lack of consistency. You might eat 4,000 calories on Monday and feel so stuffed that you only eat 1,500 on Tuesday.
To see results, you have to be relentless.
You need to eat even when you aren't hungry. This is the part people don't tell you: gaining weight quickly can be just as mentally taxing as losing it. It feels like a chore. You have to treat eating like a job.
The Importance of Sleep and Digestion
If you aren't sleeping, your cortisol is high. High cortisol can lead to muscle breakdown, which is the opposite of what you want. Aim for 8-9 hours.
Also, watch your gut health. If you start eating 3,500+ calories and your digestion breaks down, you won't absorb those nutrients. You'll just end up with a stomach ache and no weight gain. Use digestive enzymes if you feel excessively bloated, or stick to "vertical diet" principles—focusing on easily digestible foods like white rice, potatoes, and oranges rather than gas-heavy beans or broccoli.
Practical Steps to Start Today
Don't wait until Monday.
First step: Go to the store and buy a bag of white rice, a jar of almond or peanut butter, and a bottle of extra virgin olive oil.
Second step: Add one tablespoon of oil to every single meal you eat. You won't see it, and you'll barely taste it, but that's an extra 400-500 calories a day right there.
Third step: Start tracking for exactly three days. Don't guess. People are terrible at guessing. Use an app to see what your "normal" is, then intentionally add 1,000 calories to that number.
If the scale doesn't move after a week, add another 500. It’s a game of numbers. Physics doesn't care about your "fast metabolism"—if you put more energy into the system than the system expends, the system must grow.
Why Your Strategy Might Fail
Most people fail because they try to "eat clean."
Eating 4,000 calories of chicken breast and steamed spinach is practically impossible. Your stomach isn't big enough. You have to embrace "dirty" healthy foods. Honey, maple syrup, white rice, butter, and heavy cream. These are tools. Use them to bridge the gap between your current weight and your goal weight.
Once you hit your target, you can taper back to a maintenance level. But for now, if you are serious about how do i get fat quickly, you have to prioritize density over volume. Stop eating big salads. Start eating dense bowls of rice, meat, and fats.
The weight will come. Just stay consistent.
Actionable Summary for Rapid Gain
- Calculate your TDEE (Total Daily Energy Expenditure) and add a minimum of 700 calories.
- Drink your calories using high-fat, protein-dense shakes at night.
- Prioritize fats like olive oil, avocado, and nuts to increase density without increasing food volume.
- Reduce unnecessary cardio and focus on heavy lifting to ensure some of that weight is lean mass.
- Eat every 3 hours. Never let your blood sugar stay low for long; keep the storage signals active.
- Salt your food. It helps with digestion and keeps your appetite up by making food more palatable.