Q&A: Can I Lose X Pounds In Y Time Doing Z?

I am often asked questions that take the form of, “Can I lose X pounds in Y time doing Z?” The person asking usually wants to lose a large amount of weight very quickly without actually having to work very hard for it or change their diet. In fact, changing their diet is almost never part of Z and when it is it usually involves a ridiculous fad or bogus supplement. It is frequently the second or third time the person has asked some variation of the question despite having been told “no” before and doing Z anyway and predictably failing to lose fat. But, they keep asking because they would rather keep looking for a short-cut than having to work to earn the body they want.

There are no short cuts, though. None. Zip. Zilch. Zero. Diddly-squat. There are no pills you can take (that are legal and/or won’t probably kill you), no wraps or suits you can wear, no secret foods you should eat, no fun group activities that “melt fat” off your body. There are no effective fat loss methods that are either easy or fun and anyone who tells you otherwise is either ignorant or lying.

Fortunately there are ways to lose fat that are very effective, but they take time and effort. They only work if you work. Still here? Great! I’m going to tell you a few things you probably don’t want to hear but need to know to lose fat as safely, efficiently, and effectively as possible.

Question: So, can you lose X pounds in Y time doing Z?

Answer: Unless X and Y averages out to around one to two pounds of fat per week and Z involves calorie restriction the answer is almost always going to be no.

Fat Loss Takes Time and Effort

You can’t out-exercise a bad diet.

Trying to lose fat by burning more calories through additional physical activity alone is a very inefficient, very slow way to eventually lose very little fat. There are no activities you can do for thirty to sixty minutes a few times a week that are going to burn enough additional calories to result in a noticeable rate of fat loss. Doing more than that doesn’t help much, either, because increases in calorie expenditure quickly level off above moderate activity levels (1). Even if you perform one to two hours of hard physical activity daily depending on your size you might only burn enough additional calories to lose about one pound of fat per week.

No matter how many additional calories you’re able to burn through activity weekly it is not going to make a difference unless you are also restricting your food intake because the extra activity will increase your appetite likely causing you to consume even more. Also, such high a high volume and frequency of intense, usually repetitive high-force physical activity is impractical and unsustainable for most people and can lead to muscle loss and joint and spine problems over time.

If you want to engage in regular physical activity do so because you enjoy the activity or for other benefits like socializing or stress-relief or learning a useful skill, but don’t waste your valuable time doing things for the sole purpose of burning calories.

Instead you should focus on the other side of the equation and reduce your calorie intake. It is a far more time efficient and effective way to create a calorie deficit. There are formulas you can use to estimate how much you should eat or you can measure and record everything you eat, gradually reducing your average daily calorie intake week by week until you are losing about a pound or two of fat per week. If you are very fat you can lose a little more, and if are very lean you should aim for less if you want to maintain muscle mass, but for most people between one and two pounds per week is a safe and sustainable rate.

You didn’t gain it overnight, and you’re not going to lose it overnight either.

There is a limit to how quickly you can lose fat, which is proportional to how much fat you have (2). You can only get so much energy from every pound of fat on your body per day, and if you try to create a calorie deficit so large that the difference between what you eat and what your body needs exceeds what your body can get from its fat stores, it is going to take the rest from your lean body mass. You do not want to lose lean body mass, because it will reduce your metabolic rate slowing down fat loss further. Also, losing your muscle mass along with fat will not make you leaner or improve your body shape, it will just make you smaller out of shape person.

The most effective kind of exercise for fat loss is not the fun or easy kind.

Speaking of muscle mass, what you should be doing for additional physical activity is strength training. Not because it burns additional calories both while you’re doing it, not because it causes your body to continue to burn more calories for hours afterwards, but because a proper strength training program helps to prevent muscle loss or even increase your muscle mass while you’re losing fat to maintain or increase your metabolic rate.

You don’t have to work out very long, and you don’t have to work out very often. In fact, you should keep your workouts relatively short and limit them to no more than three non-consecutive days per week. If you want your workouts to be effective, however, you do need to work very hard. A good starting point for most people is to perform two or three full-body workouts per week consisting of one set of one or two exercises for each muscle group. Each exercise should be performed using relatively slow, controlled movements, using a weight that allows for the completion of at least a moderate number of repetitions in strict form (for example, lifting the weight in four seconds, holding briefly, lowering the weight in four seconds, and repeating for six to ten repetitions). This allows you to maintain more consistent tension on the target muscles making the exercises more challenging while reducing the stress on your joints and lowering your risk of injury. For examples of strength training workouts and guidelines for performance read High Intensity Workouts.

While there are some supplements that can help with fat loss (mostly stimulants like ephedrine, caffeine, green tea catechins, etc.) the effects are relatively small or only last for a short time and are only noticeable if you are also restricting your calorie intake. No supplements (that are legal and safe) will increase your metabolic rate enough to cause you to lose fat without also changing your diet. Anything that would increase your metabolic rate enough to burn as much as quickly as some fat-loss supplement advertising claims to would likely lead to dangerous increases in body temperature, dehydration, and other harmful or even fatal side-effects, and not be legal for sale without a prescription. Stick with relatively inexpensive and proven supplements like ephedrine and caffeine (in reasonable amounts) but don’t expect them to do all the work.

In summary:


  1. Try to create a calorie deficit by increasing physical activity alone.
  2. Neglect strength training to maintain your muscle mass and metabolic rate.
  3. Depend on fat-loss supplements to help if you don’t change your diet.


  1. Monitor and restrict your food intake to create a moderate calorie deficit.
  2. Strength train properly to increase your muscle mass and metabolic rate.
  3. Optionally supplement your diet and strength training with proven fat-burners like ephedrine and caffeine.


  1. Pontzer H, Durazo-arvizu R, Dugas LR, et al. Constrained Total Energy Expenditure and Metabolic Adaptation to Physical Activity in Adult Humans. Curr Biol. 2016;26(3):410-7.
  2. Alpert SS. A limit on the energy transfer rate from the human fat store in hypophagia. J Theor Biol. 2005 Mar 7;233(1):1-13.
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