Pros And Cons Of A Large Calorie Deficit

This is going to be a short, sweet, and to the point article looking at calorie deficits, and in particular, the pros and cons of implementing a large calorie deficit to reach your physique goals.

For the purpose of this article, we’ll be defining a ‘large’ calorie deficit as one that calls for a deficit of 25% or greater below your daily maintenance requirements.

Maintenance calories – the daily energy intake to maintain current bodyweight

cutting the calories with a large calorie deficit will hurt your results for sureA lot of new, and even experienced dieters want quick results, they want to go from porky to sculpted in some super silly time frame, a month or two, and if they have significant body fat to lose, doing it the ‘slow and steady wins the race’ route, will cause them mental anguish and probably an inability to sustain the diet, in their minds at least.

The reality is that large calorie deficits can work, particularly in the short-term, but the adherence rate over medium to longer terms is not so rosy, and on that basis, selecting a more moderate deficit is probably your best bet, especially as your level of leanness improves.

It’s often suggested that aiming to lose 1/2 to 1 percent of your bodyweight per week is a reasonable target, sometimes very obese people can aim a little higher. As you get leaner, you need to downgrade your weekly fat loss goals. When you are very lean, you might only be able to look to 1/4 to 1/2 pound of fat loss per week.

I speak to my training and nutrition clients all the time, and most of them think that they can lose 3-4 lbs per week on a regular basis, and look at me with a disapproving look when I tell them that they should focus on smaller, more sustainable losses, and make the eating plan I offer them, a permanent part of their lives, not just a quick fix for fast fat loss, and the rebound weight gain that can occur after severe, prolonged calorie restriction.

But, if you are the type of person who just can’t do ‘slow and steady’, this article will give you my via on the pros and cons of a large calorie deficit. You can then decide for yourself whether the benefits and negatives are worth the misery (it’s not always miserable, especially if you make good food choices).

Pros Of A Large Calorie Deficit

  • Almost immediate results and gratification. Significant ‘weight’ loss in the early stages of a diet can improve motivation and adherence.
  • The fastest rate of fat loss can occur with a large calorie deficit. You need to balance this with the potential for metabolic slowing which can occur after prolonged calorie restriction. Probably not an issue in the short-term. Using diet breaks where you eat at maintenance levels for a couple of weeks every now and then can reset hormone levels and keep the fat loss progressing when you restart your restriction.
  • Large deficits give a larger margin for error. If you make a mistake, or eat 4 muffins when you really shouldn’t, the deficit gives you a greater window to still be below your maintenance calories and not gain fat. Be mindful that weekly calories are a better metric to use than daily fluctuations. Average over a week should be the number you are really concentrating on.

Cons Of A Large Calorie Deficit

Unfortunately for some, the cons list is twice the length of the ‘pros’ list, and this should flag at least a warning or two with you. Even with the cons, short-term large deficits can work to kickstart your diet program.

  • Increased muscle loss is a real concern with larger calorie deficits, particularly in folks who are already lean and have little fat to lose.
  • Requires much more will power and determination to maintain the diet. Extreme deprivation is too much to handle for all but the toughest of folks with iron wills.
  • Deprivation can lead to falling off the diet completely, or binge eating. It is these extremely restrictive diets that lead to yo-yo dieting.
  • A poor choice for those in high performance activities. It is hard, if not impossible to keep progressing in your activity if your energy intake is too low to sustain recovery and muscular adaptations and growth. Many strength trainees will expect to lose strength during a severe ‘cutting’ phase.
  • Resting metabolic rate can be down-regulated, causing the body to slow metabolism as it experiences ‘starvation’ levels of food intake. This often happens with dieters who plateau, reduce calories, plateau, and keep reducing until they have nowhere else to go. A gradual increase in calories over time to a maintenance level can reverse the effects of metabolic slowdown.
  • Crash diets are usually a failure, this is well documented. If one fails to set up their large calorie deficit correctly, most are destined for failure.

The statement I just made included the line,

If one fails to set up their large calorie deficit correctly, most are destined for failure

So, from that, you might assume that there IS a way of utilising large calorie deficits effectively. I’m not a fan of them for the general dieter, but used as a short-term tool, for a few weeks, large deficits can result in serious fat loss, you can get lean in a matter of weeks rather than months.

That said, you have your whole life ahead of you. Unless you are needing to lose fat quickly for a modelling gig, or for a fitness show, it’s probably best avoided.

I’ve just written a post on my ‘90 days to a six-pack‘ challenge, where I am in fact, implementing some pretty large calorie deficits on my rest days. This calorie cycling, where I eat much closer to maintenance calorie level on training days, and then have a big deficit on rest days can be quite a nice way of eating. You have your low days when you’d probably like to eat more, but the next day is a training day, and the chance to eat plenty of food is all too real.

For me, it ends up as 3 higher calorie days, and 4 lower calorie days per week. As mentioned, the weekly average is what matters and you could do just as well eating moderate calories 7 days per week, but on a personal note, I enjoy the big eating days, so it works for me.

There you go. A few of the advantages and disadvantages of eating with a large calorie deficit. In 2 future posts, I’ll be considering the alternatives, moderate and small deficits to your daily intake.

If you’d like to keep up to speed, or get more involved, there are a couple of things you could do for me.

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  • Leave a comment at the bottom of this post. What sort of calorie deficits have you had success with? Do you find large deficits make you binge eat? Have you a dieting system that you could share with other readers? All comments (not rude ones) are appreciated.

That’s your lot, hope you enjoyed it

See you soon


3 thoughts on “Pros And Cons Of A Large Calorie Deficit

  1. I think the 14 X weight is to high for Maintenance. I weigh 360 lbs and have started a serious diet (60 yrs old)and work out program. I am doing Intermittent Fasting skipping Breakfast and eating between 11am and 7pm. I am walking my dog on the beach for 45 min daily and doing light dumb bell work out 3 times a week and starting to ride my bicycle around a few days a week.
    But anyway, back to the point by your calculations 14X360=5040 calories sounds a little high to me?????

    • Hey Mike

      It’s impossible to just say ‘it seems too high’, that can only be judged if you eat to those calories for a couple of weeks, and see what happens. At 360 lbs, I think you could probably do with losing some body fat and eating around the 10 cals per lb bodyweight for a while. Also, the light dumbbell work is kinda pointless unless you have some underlying reason why you can’t do heavy lifting? Get in touch via email if you want to chat some more. Happy to help, and as long as you are happy getting into some sort of exercise ,that is fantastic, but for building some lean muscle mass and shedding fat, you probably need to dial things in a little more.

      Good luck with it, and thanks for getting in touch

  2. Hey Steve, I sarted doing a Ketogenic diet about 3 weeks ago, I m complementing it with daily walking (and some intermitent fasting). I used some maintainance calories calculations, and I came up with about 2800 calories a day, but when I did the math of how many calories I m consuming daily, I get under half of that (about 1200 give or take), the thing is, I m not hungry at all (sometimes I even force myself to finish the food), I have lost 20 pounds in three weeks (started at about 300), anyway, I read somewere that more than 30% restriction was not advised, but from your checklist of pros/cons, no cons seems to apply to my case since its not requiring any willpower to follow the diet… (maybe the slower metabolism, but seems dumb to eat more just to maintain resting metabolism, besides, as I said, I dont want to eat more) So the question is, is there any other risk to eating so few calories?
    Thanks in advance,

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