How to Lose Fat in Your 30s and 40s

I was a fattie for years.

Double-chin, man boobs, “big old momma’s butt…” you name it, I had it.

I tried a number of different diets but always fell off the wagon. I’d lose a few pounds here and there, then gain it all back.

I couldn’t figure out why what had worked in the past didn’t seem to work now.

Why couldn’t I just man up and fix it?

Where did I drop that chalupa?
Where did I drop that chalupa?

To be fair, nobody ever accused me of being the sharpest tool in the shed. It took me a while to realize that I was in a different place in life, one that didn’t lend itself to the fat-loss approach I’d used in my twenties. And, honestly, I didn’t have that level of discipline, anyway.

With a corporate job and a growing number of other commitments, time really was at a premium. As was motivation. I had zero interest in carrying a massive lunch box with three tons of Tupperware to the office, just to make sure I ate my six small meals a day.

“Stoke the metabolic fire?” Forget it.

Then I discovered intermittent fasting. I read everything I could on the subject, primarily at Leangains, a site published by the very talented and knowledgeable Martin Berkhan.

And what an epiphany! Finally, a sustainable way to lose fat and keep it off… without giving up social engagements or carrying a microwave around with me.

Intermittent fasting was the primary technique I used to finally leave obesity behind and build a body I could be proud of.

Intermittent fasting is not the only way to achieve your goals. But it is the method that worked for me and many others around the world. That simply means that it was the best method for us. It may be the best for you as well.

Keep reading for everything you need to know to ditch the pot belly and double-chin.

Fasting Overview

“When a person has had too much to eat, fasting is the smartest thing he could do.” –Mark Sisson, Mark’s Daily Apple

What is fasting?

Generally speaking, fasting is abstinence from some or all types of food or drink. It’s a practice most commonly associated with religions such as Christianity and Islam. In the health and fitness world, fasting is abstinence from food for an extended period of time.

What is intermittent fasting?

Intermittent fasting (“IF”) is a period of fasting followed by a period of eating. The time periods for eating and fasting are consistent every day. For example:

PeriodExample 1Example 2Example 3
FastingMon 8 p.m. – Tue 12 p.m.Mon 9 p.m. – Tue 1 p.m.Mon 10 p.m. – Tue 2 p.m.
EatingTue 12 p.m. – Tue 8 p.m.Tue 1 p.m. – Tue 9 p.m.Tue 2 p.m. – Tue 10 p.m.
FastingTue 8 p.m. – Wed 12 p.m.Tue 9 p.m. – Wed 1 p.m.Tue 10 p.m. – Wed 2 p.m.

Benefits of intermittent fasting include increased focus or concentration, improved blood lipid profiles and, surprisingly, appetite suppression.

Your body expends for everything it does, including breathing. When no food is available to convert to energy, your body will use stored energy — such as fat tissue — instead. Fasting increases the period of time during which no food is consumed and, consequently, the period of time in which it burns off stored energy.

You see, your body’s levels of insulin decrease during fasting. Insulin actually inhibits lipolysis, or fat-burning.1 Fasting also increases catecholamines (adrenaline and noradrenaline), which increase your body’s energy levels and trigger the release of lipase, an enzyme that breaks fats into fatty acids to be used for energy.2

Don’t I NEED breakfast?

Contrary to popular belief, breakfast is not the most important meal of the day. As we’ll see shortly, your body doesn’t require food as frequently as people believe to avoid starvation and catabolism (muscle-wasting).

Many “experts” will confidently tell you that people who skip breakfast are generally fatter. That is certainly true… with a big caveat. Although those experts vaguely refer to “studies” and “research,” they fail to dig deeper.

For example, researchers used a 2003 study to conclude that “people who eat cereal (cooked or ready-to-eat cereal) or quick breads for breakfast have significantly lower body mass indices than those who skip breakfast.”3

However, the study was sponsored in part by Kellogg-USA, who just might be interested in encouraging people to eat breakfast. Also, they made a few interesting observations worth noting:

  • “Subjects who skip breakfast are already overweight… it cannot be determined whether the association is causal or correlational.”
  • Some of the groups studied “appear to represent people ‘on the run,’ eating only candy or soda, or grabbing a glass of milk or a piece of cheese. Their higher BMI would appear to support the notion that ‘dysregulated’ eating patterns are associated with obesity.”

Skipping breakfast won't make you fatPeople who skip breakfast tend to be overweight, and may be skipping breakfast to try to slim down. They also tend to have “dysregulated” eating patterns. If you eat junk, your body just might “reward” you accordingly.

I know, I know… blows my mind, too.

When in doubt, question the source. Recognize that the food industry benefits from sales. There’s nothing wrong with that… they are, collectively, a business. That said, is it possible that pushing you to eat breakfast, whether or not you’re actually hungry, might be more beneficial for them instead of you?

Shouldn’t I eat every 3 hours for my metabolism?

This is an example of conventional wisdom that actually has no scientific basis.

Researchers the University of Nottingham Medical School determined that neither metabolism nor body temperature were lowered in adults who fasted for 12, 36, and 72 hours.4 Another study at the University of Vienna also found a significant increase in metabolism during fasting.5

Fasting appears to boost the blood levels of the catecholamine norepinephrine, also known as noradrenalin. One of the “fight or flight” hormones, norepinephrine is one of six hormones that induces lipolysis, and may also increase metabolism.5

Metabolism won’t actually slow down until someone has fasted for four days.6 We will be fasting for less than 24 hours.

So why does this rumor persist? Probably due, in large part, to the bodybuilding crowd. It’s likely that they continue to push this belief because (1) bodybuilders who came before them ate that way and (2) their caloric goals are significantly higher — often over 7,000 per day! Of course it’s easier to spread that demand over six, seven, or eight meals.

Our goals are different. Even when it’s time to switch from fat loss to muscle building, we still won’t need that many calories. And if you decide to join the ranks of fitness competitors, you can still use intermittent fasting to get there. People like Seth Ronland and David Höök have done so.

Isn’t it ultimately just about calories?

Not exactly. While it’s true that cutting calories will cut weight, that’s a generalization so broad that it deserves an asterisk as big as Hillary Clinton’s affinity for lying.

There are two possible results when losing weight:

  • You lose fat and muscle (“lean body mass”), which means you look “skinny fat” until you’re just “skinny.” Yuck.
  • You lose fat while preserving the majority of your lean body mass, resulting in a lean and fit look. Sign me up!
  • With the Tekton Body approach, we opt for the latter result. To do so, we eat at least 1 gram of protein per pound of body weight. We’ll get into specifics later in this article.

How much fat will I lose?

Assuming full adherence to this protocol – fasting, macronutrients, and training – a relatively healthy adult male can get down to 10% body fat without too much trouble. It will take time, but it’s definitely achievable. Dropping into the single-digits requires patience and robust adherence to the details of our protocol.

Although we can use the scale to track general progress, monitoring decreases in body fat is the best way to truly measure progress. The BOD POD® is one of the best and most affordable methods for measuring body fat percentage. I pay $49 for testing in the Tampa area.

Supplement body fat testing with selfies and waist measurements, both for tracking purposes and for motivation.

Intermittent Fasting for fat lossFinally, you’ll start to notice a difference in how your clothes fit. Perhaps embarrassingly so. I waited until it was painfully obvious that my pants were too big: instead of my formerly-large belly pushing the waistline down, it was sagging because I couldn’t cinch my belt any tighter. A great problem to have!

How fast will I lose fat?

While everyone is different, Martin has some general guidelines:

Body Fat PercentageWeekly Weight Loss
18 – 19%1.7 pounds
15 – 17%1.5 pounds
12 – 14%1.3 pounds
9 – 11%1 pound
< 8 %.7 pounds

I started at 218 pounds and approximately 30% body fat, and lost an average of 2 pounds per week over the course of several months.

How to fast

How long should I fast?

I teach the “16/8” method, where you fast for 16 hours and eat over the course of 8 hours. This method was developed and popularized by Martin. He found through clinical experience that fasting for 16 hours struck the optimum balance between fat loss and muscle retention, while minimizing hunger.

What hours should I fast?

I recommend that you fast before noon and after 8 p.m. That places the majority of your fast during your sleeping hours, which helps with adherence. Also, this schedule generally allows you to participate in social events without going hungry.

Won’t I be hungry when I wake up?

At first, yes. As with most things related to the mind and body, there is an adjustment phase. While the schedule I teach places most of the fast during sleeping hours, the typical fast does last until noon, which can seem like a long time if you’re accustomed to eating breakfast.

Personally, I did experience some hunger early on. As I became more experienced with fasting, the onset of hunger “pains” moved back later in the morning. This is probably due to the role of ghrelin, a hormone that regulates appetite.7 As ghrelin rises, so does your appetite. Researchers have found that ghrelin actually rises “in anticipation of an expected meal.”8 In other words, if you train your body to expect food all the time, you’ll be hungry all the time!

These days, I usually get hungry around 11 a.m. I’ve found that drinking a lot of water in the morning minimizes those feelings.

I need to fast all day for religious reasons

That’s fine. A few days of eating a smaller amount of calories will not negatively impact your progress.

There are, of course, various protocols for religious fasting. As a Catholic, I fast a few times throughout the year. For Catholics, fasting is essentially defined as one “full meal” and two smaller meals that, when combined, do not equal a second full meal. It’s rare for me to even get 1,000 calories on those occasions. I haven’t suffered at all because of it… my muscles haven’t wasted away, nor has my deadlift dropped 50%. If anything, those fasts help me appreciate the next day all the more!

How many calories do I need for fat loss?

There is a general rule of thumb, and then there’s a more scientific approach.

First, the general rule of thumb. Take your bodyweight in pounds and multiply it by 12. This will equal your daily maintenance requirements. Now, subtract 20%. This is your target daily caloric intake. For example, consider a 220 pound man:

  1. 220 x 12 = 2,640 daily maintenance requirements
  2. 2640 x .2 = 528
  3. 2640 – 528 = 2,112 maximum daily calories to facilitate weight loss

A more accurate approach utilizes the Katch-McArdle formula, and adjusts based on whether or not you are training that day. This approach gives your body the calories it needs to appropriately recover from training.

BMR = 370 + (9.79759519 x Lean Mass in pounds)
Daily Maintenance Requirement = BMR x TDEE

Training Day Requirement: Maintenance x 90%
Rest Day Requirement: Maintenance x 70%

BMR = Basal Metabolic Rate. This number equals the number of calories your body needs for base functions, such as breathing and maintaining a healthy body temperature.

TDEE = Total Daily Energy Expenditure. This is a multiplier against your BMR, based on your activity level:

Sedentary1.2Little or no exercise, desk job
Lightly Active1.375Light exercise/sports 1-3 days/wk (This will be most of you)
Moderately Active1.55Moderate exercise/sports 3-5 days/wk
Very Active1.725Hard exercise/sports 6-7 days/wk
Extremely Active1.9Hard daily exercise/sports and physical job or 2X day training (e.g., marathon training, etc.)

Consider the same 220 pound, office-chained male, assuming 30% body fat:

  1. 220 x 70% = 154 lean mass in pounds
  2. 370 + (9.79759519 x 154) = 1,879 BMR
  3. 1,879 x 1.375 = 2,584 daily maintenance requirement
  4. 2,584 x .9 = 2,326 training day requirement
  5. 2,584 x .7 = 1,809 rest day requirement
    Note: All products rounded

I can’t eat that much at once

First of all, this is rarely a problem. That said, you may occasionally find that you aren’t eating enough, especially if you are eating more filling foods. Second, remember that you have eight hours in which to eat your fill. It’s unlikely that you’ll under-consume!

In all actuality, it’s easy for fasting newbs to overeat. Don’t fall into the trap of giving yourself a free license during the eating period. A simple tip to prevent this is to make sure that you are eating at least 30 grams of protein with every meal. That will help with satiety.

Although it’s not required, you will find faster success by paying attention to macronutrients (discussed in more detail here). Be sure to spread your calories — especially protein — throughout the day, so you don’t end up with 200 grams of protein (the equivalent of six chicken breast) to cram down your gullet with 20 minutes left in your eating window!

How low can I drop calories?

Generally speaking, the lowest you should go is 1,200 calories on any given day. Honestly though, you won’t need to drop them that low in order to lose fat.

What should I eat?

Eat healthy. You know what isn’t healthy, and the list is too long for this article, anyway. Following is a short list of some of the foods you can include, grouped by primary macronutrient:

Coconut Oil
Extra Virgin Olive Oil
Fish Oil
Flax Oil
Natural Peanut Butter
Omega 3 Eggs


Chicken Breast
Cottage Cheese

Do your best to make sure your daily caloric totals reflect the following percentages:

MacronutrientTraining DaysRest Days

Doing so — in conjunction with a good training program — will help ensure that you get leaner without looking like an invalid.

You’ll note that protein intake is higher than average on this plan. Consuming at least 1 gram of protein per pound of body weight is essential for retaining muscle mass while dieting.9

The astute reader will note that the ratios above lead to higher protein consumption, up to 1.5 grams per pound of body weight, depending on one’s weight. This is because protein is very filling. It’s a lot harder to overate when protein is high, versus higher carbohydrates or fats.

So, run the steer by the table and grab a slice!


When should I train?

Honestly, it’s entirely up to you. I train shortly after waking up, but train at a time that works best for you. There is nothing wrong with training at 10 a.m., after lunch, or after work.

How should I train?

I cover this in more detail in How to Get Stronger, so I won’t repeat myself here. In essence, train for strength.

Isn’t fasted training catabolic?


A study by European researchers showed that subjects who trained in a fasted state — that is, they trained on empty stomachs in the morning — had increased levels of an enzyme called p70S6k kinase.10 One of the downstream impacts of that enzyme is protein synthesis, which leads to muscle growth.

Also, a study by researchers at the Research Centre for Exercise and Health in Belgium demonstrated that fasted training actually facilitated muscle adaptations, in addition to other benefits, such as improved glucose tolerance (just say no to diabetes!) and insulin sensitivity.11

So we know that a meal isn’t necessary before training. However, there are benefits to consuming 10 grams of branched-chain amino acids (BCAAs) just before training. At least one study has shown that training with BCAAs in the system “robustly” increased levels of p70s6k for one to two hours after the conclusion of training.12

My preference, based on Martin’s recommendation, is to drink 10 grams of Purple Wraath 5 to 15 minutes prior to training.

Follow this up with one serving one hour after training and another serving two hours after the first serving (or three hours after training), unless you’ve entered your eating period.

What about post-workout nutrition?

For years, bodybuilders, trainers, and nutritionists believed that your body would burn its own muscle tissue for fuel — a process known as catabolism — if you didn’t eat within 30 to 60 minutes of training. I believed that myself for quite a while. However, our understanding of how the body works continues to improve.

Remember, the post-workout window is actually 24 hours. That is, your body’s protein synthesis mechanisms begin to rise three to four hours post-workout, peak 24 hours post-workout, and then return to normal 36 to 48 hours post-workout.13

Do I need to do cardio?

No. You may find it helpful to take a walk for heart health, but it’s not necessary for fat loss. The relatively minor amount of calories burned by walking doesn’t make it the most effective or efficient tool for fat loss.

That said, I often took a 40 minute fasted walk on non-training days. Why? Because our 11 month old liked to wake up at 4 a.m., and it’s hard to keep a crabby baby quiet enough to avoid waking the rest of the house!

What about HIIT or sprinting?

Stay away from these kinds of activities while you’re cutting fat. You will get more than enough activity in with weight training, and you may risk over-training if you do too much.


How much water should I drink?

No need to go overboard here. Drink just enough to have four or five clear urinations every day. Try not to drink too much water after dinner so you don’t interrupt sleep to go to the bathroom in the middle of the night.

What about diet soda?

Diet soda is fine. The research into correlations between diet soda and weight gain are inconclusive at best. Some studies have concluded that drinking diet soda causes sugar cravings, which lead some people to satisfy those cravings by — guess what? — eating sugary snacks. In other words, it’s the sugary snack that caused weight gain, not the diet soda. Click here to read a good summary on this topic.


There you have it: a proven, sustainable approach to eating for fat loss and lean body maintenance.

Have you had success with intermittent fasting? Questions? Please add a comment below or contact me privately.

References and further reading

1. Heilbronn, L., Smith, S., Martin, C., Anton, S., Ravussin, E. (2005). Alternate-day fasting in nonobese subjects: effects on body weight, body composition, and energy metabolism. Am J Clin Nutr, 81(1), 69-73. [URL]

2. Kraemer, F., Shen, W. (2002). Hormone-sensitive lipase control of intracellular tri-(di-)acylglycerol and cholesteryl ester hydrolysis. The Journal of Lipid Research, 43, 1585-1594. [URL]

3. Cho, S., Dietrich, M., Brown, C.J., Clark, C.A., Block, G. (2003). The effect of breakfast type on total daily energy intake and body mass index: results from the Third National Health and Nutrition Examination Survey (NHANES III). Am Coll Nutr, 22(4), 296-302. [URL]

4. Webber, J., Macdonald, I.A. (1994). The cardiovascular, metabolic and hormonal changes accompanying acute starvation in men and women. British Journal of Nutrition, 71(3), 437-447. [URL]

5. Zauner, C., Schneeweiss, B., Kranz, A., Madl, C., Ratheiser, K., Kramer, L., Roth, E., Schneider, B., Lenz, K. (2000). Resting energy expenditure in short-term starvation is increased as a result of an increase in serum norepinephrine. Am J Clin Nutr, 71(6), 1511-5. [URL]

6. Nair, K.S., Woolf, P.D., Welle, S.L., Matthews, D.E. (1987). Leucine, glucose, and energy metabolism after 3 days of fasting in healthy human subjects. Am J Clin Nutr, 46(4), 557-62. [URL]

7. Schwartz, M., Woods, S., Porte Jr., D., Seeley, R., Baskin, D. (2000). Central nervous system control of food intake. Nature, 404(6778), 661-71. [URL]

8. Frecka, J., Mattes, R. (2008). Possible entrainment of ghrelin to habitual meal patterns in humans. Am J Physiol Gastrointest Liver Physiol, 294(3), 699-707. [URL]

9. Mettler, S., Tipton, KD.. (2010). Increased protein intake reduces lean body mass loss during weight loss in athletes. Med Sci Sports Exerc, 42(2), 326-337. [URL]

10. Deldicque, L., De Bock, K., Maris, M., Ramaekers, M., Nielens, H., Francaux, M., Hespel, P. (2009). Increased p70S6k phosphorylation during intake of a protein-carbohydrate drink following resistance exercise in the fasted state. Eur J Appl Physiol, 108(4), 791-800. [URL]

11. Van Proeyen, K., Szlufcik, K., Nielens, H., Pelgrim, K., Deldicque, L, Hesselink, M., Van Veldhoven, P., Hespel, P. (2010). Training in the fasted state improves glucose tolerance during fat-rich diet. Journal of physiology, 588(21), 4289-4302. [URL]

12. Karlsson, H., Nilsson, P.A., Nilsson, J., Chibalin, A., Zierath, J., Blomstrand, E. (2004). Branched-chain amino acids increase p70S6k phosphorylation in human skeletal muscle after resistance exercise. Am J Physiol Endocrinol Metab, 287(1), E1-7. [URL]

13. Phillips, S.M., Tipton, K.D., Aarsland, A., Wolf, S.E., Wolfe, R.R. (1997). Mixed muscle protein synthesis and breakdown after resistance exercise in humans. Am J Physiol, 273(1 Pt 1), E99-107. [URL]

Still have questions about conventional nutrition dogma? Check out Martin’s “Top Ten Fasting Myths Debunked.” It’s an excellent read.

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