Can you lose a pound of fat per day? No, that’s not a typo, I said lose a pound of fat per DAY not per WEEK. Yeah, I know what you’re thinking (especially if you’re a regular Burn the Fat Blog or Tom Venuto reader), but don’t get yer britches in a bunch just yet, just read the darn post first, THEN let loose with your comments…
Obviously, if we were talking about weight and not body fat, we could all agree that you could actually lose MORE than a pound in a day – with ease!
I’ve cut 8 pounds overnight to make a weight class in the past (in already ripped condition no less), and I have wrestler friends who have cut twice that or more. But that’s not fat loss, that’s primarily dehydration. It’s also very transient – like I said, “overnight” (and “overnight” describes how it comes back on too!)
Weight loss and fat loss are not the same thing. So let’s get clear, in this post, we are talking about FAT LOSS.
So… CAN you lose a pound of fat per day? Can you can you huh huh huh?
How about I start right out with the answer to the question:
Yes. It IS possible… But (BIG BUTS coming)…
- Not for everyone (depends on your starting point)
- Not for long (rate of fat loss will slow with time)
- Not easily (takes butt-busting hard work and discipline)
- And, frankly, it’s just not likely to happen (for all the above reasons)
Now let me explain.
If you look at the science, you’ll usually hear that the maximum rate of fat loss that CAN realistically be achieved, for most people, is around 2.5, 3.0, maybe 3.5 lbs of fat per week. Even that will be a stretch for petite women or anyone who is short and / or small-framed and in any case, this is an above average rate of fat loss.
A rapid rate of fat loss is most likely to be achieved only by overweight and obese individuals.
People who are already at lean or even average body fat levels CANNOT lose fat that rapidly because they do not have a high enough basal metabolic rate or total daily energy expenditure. They simply cannot create a large enough deficit without hours and hours of exercise a day, if it’s possible at all. If they try to force it, they will lose lean body mass. (Overweight people can sustain a larger calorie deficit without any negative effects or fear of muscle loss).
This promise/pitch, “lose a pound of fat a day” is an old one. How long have you been seeing those ads that say, “lose 30 pounds in 30 days!” For ages right? And those fruitcake nutjobs who promote HCG for weight loss – even they claim “lose a pound a day” to sell their bogus garbage (that’s right, I said it!)
“A pound a day” has a nice ring to it (rings the register, especially).
Of course, in many of these cases, the distinction is not made between body fat and body weight. A pound a day in bodyweight is not that difficult, but it’s also not that desirable if it includes mostly water weight and other fat-free mass.
There is no science to support claims that extremely fast fat loss on par with a pound of fat per day is possible for anyone but overweight and obese people. Of course if someone is fairly lean to start with, they might not have all that many pounds of extraneous fat to lose to begin with, so thinking about “30 pounds in 30 days” may be a moot point anyway.
Programs that make these types of rapid fat loss claims usually have some new hook based on manipulating hormones, a “magic pill or potion” or some super-duper workout program….
But manipulation of hormones can only take you so far. Your body’s endocrine systems are very tightly regulated.
Most supplements are a complete waste of money (don’t even get me started today, cuz I’m in one of those moods)…
Training can only take you so far too because there are only so many hours in the day and fat loss is also a math equation involving calories in versus calories out.
Even with intense exercise for hours every day, the math still doesn’t work for anyone but very overweight or obese people. You need a 3500 calorie per day deficit to achieve a pound of fat loss in a day. Outside of a “Biggest Loser” ranch / obese person type of situation – it will NOT be practical to achieve this.
Beyond lack of practicality, it may very well be biologically not possible to exceed a certain rate of fat loss per pound of fat mass on your body.
Research from the University of New Mexico has suggested that there is in fact a limit on the amount of fat a person can transfer from adipose tissue into energy on a daily basis during a calorie deficit. Nod to Lyle McDonald, which was the first place I heard about this study a few years back.
The speed of energy transfer is, not surprisingly, based on how much body fat a person has to begin with. The research paper, titled, “a limit on the energy transfer rate from the human fat store in hypophagia,” gave a specific number on the maximum rate of fat oxidation and energy transfer:
“A limit on the maximum energy transfer rate from the human fat store in hypophagia is deduced from experimental data of underfed subjects maintaining moderate activity levels and is found to have a value of (290+/-25) kJ/kgd. A dietary restriction which exceeds the limited capability of the fat store to compensate for the energy deficiency results in an immediate decrease in the fat free mass (FFM).
This says that the limit is 290+/- 25 KJ/kg/d, which is a maximum energy transfer rate of 31 kcal/lb of fat per day.
So, if you’re a 180 pound male and you’re fairly lean at 10% body fat, you have 18 lbs of fat. 31 kcal X 18 = 558 kcal deficit. That pans out to only 1.1 lbs of fat loss per week. Beyond that you’re likely to lose fat free mass.
Now take the guy who is 280 lbs and 37% body fat, which is 103 lbs of fat. 31kcal X 103 lbs of fat = 3193 kcal per day, which is close to a pound of fat a day which could be safely lost – 6.4 lbs per week to be precise – and there you have it – how to lose a pound of fat per day” A) be obese B) create a massive 3500 calorie per day deficit.
This was published in a theoretical biology journal, so I suppose you could argue that these numbers are speculative or just estimations. However, these findings are consistent with other research which has clearly shown that obese individuals can lose fat faster than lean people (and nutrition programs and goals therefore, have to be adjusted by body type, including your starting body fat percentage)
It’s why pre contest bodybuilders usually aim for a weight loss of only about a pound a week – intentionally very slow fat loss. And it’s why contestants on the Biggest Loser could lose 6 pounds a week of pure fat or more (add water weight loss on top of that for really dramatic double-digit weekly weight loss).
Could an obese person lose 30 pounds of fat (not just weight) in 30 days?
Probably yes, although it wouldn’t be easy. Some very overweight people might not even be able to do the amount of exercise to achieve the necessary daily calorie expenditure, so even if they can biologically lose the fat, they may not be able to pull it off in the real world.
I’m not drawn to extreme approaches or rapid fat loss diets because they don’t teach lifestyle. They promote a quick-fix mentality and they may increase the risk of weight rebound.
Admittedly however, there are times when you’re up against a deadline and you MUST get maximum fat loss. That may not be impatience per se, it’s sometimes a necessity – like when you have a photo shoot, contest, filming, or even personal reasons like vacation where you have an appearance slated for the beach or the Vegas pool scene… and time is running out.
Some folks are willing to “suffer” a bit (“work hard,” if you prefer), for several weeks to get maximum fat loss despite the discomfort and discipline it requires.
I’m a proponent of teaching lifestyle change and the slow and steady wins approach… but…
Here’s my advice if you must lose fat quickly:
1. 1-2 pounds per week of fat loss is typical and it’s still good general advice. But it is possible for an active person with an average or larger frame and fairly sizeable fat reserve to realistically and practically lose 2.5 to 3.0 pounds of fat per week. Maybe 3.5 lbs. This is what I would call a rapid fat loss program, meaning that it’s faster than typical.
2. The more fat you have, the faster you can lose it; the leaner you are, the slower you must lose it in order to preserve lean tissue. Therefore, the claim that anyone and everyone can safely lose fat rapidly at a rate at or near a pound a day, regardless of their starting bodyfat, is false. If you’re very overweight, faster fat loss is possible.
3. Rapid fat loss is not for everyone. Regardless of your starting body size and body fat level, if you have ANY history of binge eating or yo-yo dieting (aka weight cycling), take the slow and steady road and focus on lifestyle habits and behavior changes. Forget about “diets” let alone rapid weight loss diets.
For more information on rapid weight loss and rapid fat loss, check out the links to the “related articles” below. For information on achieving maximum fat loss, check out chapter 12 in my e-book Burn the Fat, Feed the Muscle and look up the “PHASE III Competition Diet.”
Alpert SS, A limit on the energy transfer rate from the human fat store in hypophagia, Journal of Theoretical Biology. 7: 233(1) 1-13. 2004. University of New Mexico. [pubmed]
Hall, KD., What is the required energy deficit per unit of weight loss? Int J Obesity. 32(3): 573-576. 2008 Laboratory of Biological Modeling, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892 [pub med]