First things first, I'm a 25 year old male and I'm currently 280 lbs. I've finally admitted that there is a real problem with my lifestyle and I'm hoping to drop my body fat from about 35% to 15-20%.

However, I've been looking at numerous videos, I've been using all sorts of calculators and reading countless articles and it seems like they seem to be all differ greatly in terms of how much one should be eating.

I'm not in a rush and I understand that this is a lifestyle change more than anything and I'm actually really excited, but as for how many calories I should consume daily I'm completely lost.

I'm currently eating 1750 calories a day, I signed up for a gym earlier today and want to start doing cardio & lifting three times a week. What's the best way to determine how many calories I should really eat? I feel like 1750 might be too little but that's what MyFitnessPal put me at.

As for daily physical activity, I walk an average of 2.5 miles a day on campus but that's about it. Other than that I lead a rather sedentary lifestyle.

Any advice/help is appreciated. Thank you!

  • 3
    How quickly are you planning to lose weight? Given your size and age, I'm guessing that the 1750 calorie goal is about a 500 calorie deficit for someone with moderate activity (occasionally getting up and walking), which fits what you say for walking around campus. That's good for about a pound a week. Exercise will increase the amount of calories you burn, but take care that you're not eating more than you're burning if you're looking to lose weight. My rule of thumb is to assume that the reported calorie burn for any exercise is 100 calories more than it actually is.
    – Sean Duggan
    Commented Apr 4, 2016 at 12:05
  • @SeanDuggan - The 3500 calorie = 1 lb has been mostly debunked as well, it's going to vary from person to person and stage to stage of loss. But as long as calories out > calories in, it's good.
    – JohnP
    Commented Apr 4, 2016 at 18:01
  • @JohnP: I had not heard that the 3500 calorie amount had been debunked. I know the BMR varies (and the calculators are rough estimates) and that a) people are bad at estimating portions and b) the method of preparation can change bioavailability of those calories (you consume fewer calories with stale bread than with fresh, for example)... is that what you're discussing?
    – Sean Duggan
    Commented Apr 4, 2016 at 19:25
  • @SeanDuggan - I got called out in the comments on this question a couple of years ago, and despite being a commonly accepted number, there really isn't anything to support it, and it rises from math being badly applied. I believed at the time that 3500 cal = 1 lb for weight loss purposes was true as well. Maybe "debunked" is too strong, but it's definitely not supported with research.
    – JohnP
    Commented Apr 4, 2016 at 21:17
  • @JohnP You deserve a lot of respect for this comment. It's not an easy thing to change your mind against what we have been taught most of our lives.
    – michael
    Commented Apr 7, 2016 at 19:49

2 Answers 2


There are countless personal factors, such as your genetics, current fitness level, past exercise and daily habits, that will determine your total daily energy expenditure (TDEE). The calculators don't, and can't, take all of those into account. They can provide a decent ballpark figure, but that's about it. So instead, I suggest you simply take the empirical approach to find actual hard data that applies to you.

Since you say you are not in a rush (very wise) I suggest the following. For the following three weeks, track EVERYTHING you eat in an application such as MyFitnessPal. Eat as you usually would. Don't let the sudden awareness of your consumption habits suddenly change them. There's a first pitfall here: you must be extremely critical of all entries you find on MyFitnessPal because, my word, many of them are wrong. When consuming food with labels, cross-check any entry you haven't made yourself with the label and correct if necessary. When consuming whole foods, I like to cross-check with the Nutritiondata database, which is an excellent resource. Weigh your food using a kitchen scale (preferably an accurate, electronic one), don't just eyeball it. Use weight measurements instead of things like "cups" or "portions" because they can vary too easily. While doing all of this, weigh yourself daily and record the weight in a spreadsheet (such as on Google Drive). Preferably use an electronic scale that provides accurate information with a small resolution (down to 0.1 kg or lbs would suffice). Weigh yourself in the morning, immediately after going to the toilet but before eating or drinking something. This will give the most consistent results. There will be perfectly normal daily fluctuations in weight; ignore those. At the end of each week, take the average of the weigh-ins. That's your average weight for the week.

Now you can observe how your weight evolves over those three weeks. Does it increase? Then on average you are eating more than your TDEE. Does it decrease? You're in a caloric deficit. If it stays more or less the same, bingo, you're eating maintenance. Suppose you're 280.2 lbs the first week, 280.3 the second and back to 280.2 the third, it would be the latter case. Seeing a rising or sinking trend would indicate surplus/deficit. Find out how much you ate on average by averaging the daily calorie intake over those three weeks.

If there's weight gain, your TDEE is lower than what you currently eat. How much lower depends on the actual weight gain and absolute calorie consumption. It's the other way around for weight loss (you're eating less than TDEE). A good start for adjustment would be about 250 kcal for a male. If you're very patient, you might repeat the experiment above with an adjusted calorie intake and see whether the weight gain/loss stops (or reverses) to zone in further on the exact number.

Armed with this experimental knowledge of your TDEE, you can now decide on the calorie deficit you wish to create and stick to that by using the tracking you've become accustomed to. Let me give you a fair warning: too great a deficit cannot be maintained. Build habits that can be kept in the long run (as in, your entire life) and make the deficit a scaled-down version of what you'll be doing after you've lost sufficient weight and eating maintenance.

Good luck!

  • Before your response, I actually decided to use one calculator to somewhat estimate my TDEE, I came to the conclusion that eating 1700 calories is not only leaving me thinking about food all day but if I think ahead I cannot imagine more of a deficit down the road when I do actually lose weight. I've decided to increase my daily caloric intake to 2150 and I'm going to see by Sunday if I'm still losing weight.. I figure right now I don't care what my maintenance intake is so I'll do that when I reach my goal weight. Thank you so much for your thorough response, great to have confirmation. Commented Apr 8, 2016 at 7:55
  • @SomewhatInsane Take plenty of time to see the effects of your current daily intake. There can be large fluctuations (I once managed to gain 5 kg in one weekend and lose it again in a week; mostly water weight) so you need measurements over time to find out. The key to a successful diet is the capacity to maintain it, so a smaller deficit over a longer time is most likely going to serve you better than a bigger deficit that leads to hunger. You cannot win from hunger. It's an instinct that's been honed over hundreds of millions of years.
    – G_H
    Commented Apr 8, 2016 at 8:05

There will always be many formulas out there and no one here is going to provide you with a more authoritative formula. That being said they don't differ that much and you should be OK with any formula for weight loss for the whole being.

Once you get closer to your weight loss goal you may need to fine tune it. It sounds like you are trying to lose 2 pounds a week as at 280 your tdee is going to be pretty high. You might want to slow it down to 1 pound a week if you are not feeling OK

  • Thank you for your reponse. I'm currently just trying to lose 1-1.5 lbs a week. I've actually decided to up my calorie rate to 2150 a day and I feel a lot better, this is a lot more manageable and I don't feel like I'm starving. Commented Apr 8, 2016 at 7:54
  • That's great. Glad you found what works for you. That's the key to making it work
    – YisraelU
    Commented Apr 8, 2016 at 14:01

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