Intermittent Fasting

Jim_Resting_bar_copyIs IF right for you? Some of you may be surprised to hear that I frequently use intermittent fasting (IF).

But that doesn’t mean that I’m saying that it is something that you should do unless you fit a certain criteria. I live my life 24/7 at 4-5% body fat. I might go as high as 6% body fat during certain periods. But generally I have to be as lean as possible year-round for photo shoots, videos and appearances and using IF during certain periods helps me maintain that.

Again, I am not saying that you should start using IF, unless you have reached a certain point in your diet, as I will explain here.

Let’s break down intermittent fasting (IF). IF is a technique where you fast for a period of time and then you eat for a certain period of time and you cycle these periods. The type of intermittent fasting that I have found to work best for losing body fat and maintaining muscle is 16/8 intermittent fasting. That means that you fast for 16 hours and your feeding window lasts 8 hours each day.

Intermittent fasting has become increasingly popular in the last few years. However, I have been interested in its application for fat loss for a couple of decades. The lab that I did my postdoctoral work in at Yale University School of Medicine, along with colleagues at The University of Copenhagen, did a bit of work on fasting and fat loss in the early 2000’s.

Our group published several papers that show one of the key mechanisms in fasting-induced fat loss has to do with an increase in the activity of genes that increase the number of calories the body burns and the amount of fat it burns. More specifically, when you fast, it turns on genes that encode for certain uncoupling proteins and for enzymes that increase fat burning.

In simple terms, the uncoupling proteins basically poke holes in the mitochondria inside muscle cells. The mitochondria are where most of your energy is derived from, especially at rest. By poking “holes” in the mitochondria they produce less energy, so they have to burn far more calories to produce the same amount of energy in the form of ATP. In other words, when you fast you burn more calories and fat. What’s interesting is that our lab found that when you finally eat after fasting the activity of many of these genes are increased even further.

Research shows that fasting may also work through a number of other different mechanisms that lead to increased calorie and fat burn and leads to enhanced fat loss. Research also suggests that fasting provides numerous health benefits, such as lower cholesterol and triglyceride levels, higher HDL (good) cholesterol levels and even greater longevity. One study also found that intermittent fasting in men increased red blood cell and hemoglobin levels in the blood.

Hemoglobin is the protein in red blood cells that carries oxygen in the bloodstream to the muscles. Increasing red blood cells and hemoglobin levels is what endurance athletes like cyclists are trying to increase when they illegally “dope” with EPO (erythropoietin), yet IF may do this naturally.

Some proponents claim that IF even benefits muscle building. But this is where I disagree with their logic. There really is no research suggesting that IF benefits muscle growth over a traditional diet. In fact, from my personal experience and the data that I’ve collected over the years, it would appear that IF would limit muscle growth as compared to following the rules covered in Chapter 26 for eating to maximize muscle growth.

But it shouldn’t cause muscle loss as some worry, at least in normal-sized people. One study in men during Ramadan found that the men lost no muscle mass with this form of IF (fasting during the day and eating only between sunset and dawn), yet lost a significant amount of body fat. However, some heavily muscled guys have reported that IF does not allow them to maintain their muscle mass and they tend to end up losing some.

There is no debating the fact that intermittent fasting works well to enhance fat loss. However, it is not a method of dieting that needs to be used from the get-go. Instead, I recommend using it once you’ve hit a plateau and you can no longer lower carbs and calories. Since you want to keep protein and fat as high as possible, IF allows you one more step before you need to start whittling away at those two critical macros to lower calories and continue losing body fat. You should first slowly lower your carbs over time. For an article on how to do so, check out my Dieting For Fat Loss 101 article.

Once you get down to about 0.25 g of carbs per pound of body weight, it will be impossible to lower carbs any more. That’s because most of the carb sources making up the 0.25 g per pound are coming from the carbs in protein powders and from vegetables. These carbs are fairly unavoidable and also are a good deal of fiber, which you need.

Another reason to wait to use IF after you have eliminated most of your carbs is that IF works very well with a low carb diet. The work from our lab at Yale found that when you fast and then refeed with a low-carb meal the activity of the genes that increase calorie and fat burning are further increased with the meal. However, when you refeed with a higher-carb meal the activity of many of these genes are decreased. So following IF with a low-carb diet helps you to maximize calorie and fat burning.

Another reason why you want to wait till a later stage in your diet to introduce IF has to do with total calorie intake. When you only have an 8-hour window to eat, you often cannot consume as much food as when you can eat all day. This is one of the fringe benefits of IF. It automatically limits calorie intake. If you start using IF early on in your diet, you may not be able to consume enough food during your feeding window, which will make it hard to drop calories in later stages as your fat loss plateaus.

Since you are cramming so many meals into an 8-hour time frame, meals will come more frequently than you were previously eating. Meals will be maybe an hour or two apart and as soon as 30 minutes in some cases. If you find that you cannot consume this many meals, you can also combine some of them. In the sample meals below, the snack that comes before dinner is a protein shake and peanut butter. You can have this shake with dinner and enjoy the peanut butter as a dessert.

For the average Joe or Jane, the time of day you fast and the time of day you eat makes little difference. However, for those who work out, like ALL the members of jimstoppani.com, should manipulate their fasting and feeding windows based on when they train.

If you train in the morning, then I suggest that you start your 8-hour feeding window with your post-workout meal. That means that you would train completely fasted and your first meal would be your post-workout shake. But since you skipped your pre-workout shake your post-workout shake should include both your pre- and post-workout shakes and supplements.

For example, if you train from 7:00 am – 8:30 am, then your feeding window starts at 8:30 am with your post-workout shake and ends at 4:30 pm with a snack of slow-digesting protein. If you train in the morning, yet ending your feeding window in the late afternoon is too early for you (you want to eat dinner later with your family, etc…) then you could postpone your post-workout shake by 2-3 hours. It’s not ideal for maintaining muscle mass, but it certainly will not hamper fat loss.

One note about BCAAs: Some recommend sipping on branched-chain amino acids (BCAAs) during their fasting period to better preserve muscle. While this technique would definitely help with preserving and building muscle, it is technically putting you in a fed state. In other words, you are not truly fasting. Amino acids combine to form protein — there are 20 amino acids that are used as the building blocks of protein. These include the nine essential amino acids leucine, isoleucine, valine, tryptophan, threonine, phenylalanine, methionine, lysine, and histidine, as well as the 11 nonessential amino acids arginine, serine, cysteine, glycine, proline, alanine, tyrosine, aspartic acid, asparagine, glutamic acid, and glutamine.

If you consume just one of these amino acids, you are essentially consuming protein and therefore technically are not fasting. The BCAA amino acid leucine poses a special problem with IF. This is because the brain uses blood leucine levels as an indicator of how fed the body is. So if you’re sipping on BCAAs, the leucine is signaling the brain that you are currently well fed.

Although no work has been done on this issue during fasting, it is easy to project that if the brain senses you are fed, then the benefits that come from fasting may be compromised. My suggestion is to avoid BCAAs and any of the 20 proteinogenic amino acids (those used in the building of proteins) until you are in your feeding period.

One exception for using BCAAs during fasting is if you train in a fasted state. Here you can sip on BCAAs during the workout, along with the ones I mention below. This is because when you are exercising, the BCAAs are a powerful source of energy for the muscles. And since you are just sipping on a drink with BCAAs in it, you are not pounding a bunch of them. Here the benefits of BCAAs for your workout outweigh any potential negatives on fasting.

Amino acids that are not proteinogenic and are just functional amino acids can be consumed during fasting. Here I am talking about amino acids like beta-alanine, betaine, D-aspartic acid, and even though they are not amino acids (but some people classify them as aminos), carnitine and creatine. These are fine to sip on during the day, especially if you are training in a fasted state.

The sample meal plans below show you how to apply intermittent fasting for the four main training time points throughout the day. While I suggest that you schedule your fasting and eating around the time you train, you can also adjust the time you train to better match when you want to fast and eat.

For example, let’s say that you normally train in the morning, but find that it’s almost impossible for you to fast at night because your cravings are so strong at night. In that case, I would highly suggest training later in the day, so that you fast in the morning and eat at night when your cravings are high.

Although the meals in the sample diets below, still list breakfast, lunch and dinner, these meals may not necessarily be consumed at the “normal” time for that meal. For example, in the morning workout example below, if you finish your workout at 8:00 am and consume your post-workout meal at this time, your feeding window ends at 4:00 pm.

That means that lunch will be consumed some time before noon and dinner would be consumed probably before 3:00 pm. These sample diets provide about 11 calories, 1.5 g protein, 0.25 g carbs, and 0.5 g fat per pound of body weight for a 200-pound person. That means that they provide about 2100 calories, almost 300 g protein, about 50 g carbs, and about 100 g fat.

Sample IF meal plan for those working out first thing in the morning:

During workout (drink during workouts)

  • 5-10 grams BCAAs
  • 2-5 grams creatine (depending on form)
  • 2-3 grams beta-alanine
  • 1-2 grams of betaine

Postworkout (within 30 minutes after workouts – this starts your 8-hour eating window)

  • 40-60 g protein from a mixed protein powder (Whey/Casein)
  • 5-10 grams BCAAs
  • 2-5 grams creatine (depending on form)
  • 2-3 grams beta-alanine
  • 1-2 grams betaine
  • 2 grams L-carnitine or L-carnitine L-tartrate
  • 2-5 grams glutamine

Breakfast (after 30 minutes after postworkout meal)

  • 20-30 g protein of a mixed protein powder (Whey/Casein)
  • 3 whole eggs
  • 3 egg whites
  • 1 tsp Olive oil

(scramble eggs cook in olive oil )

Late-morning snack

  • 1 cup low-fat cottage cheese

Lunch

  • 6 oz. can albacore tuna
  • 2 cups mixed green Salad
  • 1 Tbsp salad dressing (olive oil n vinegar)

(add tuna to salad)

Snack

  • 20-30 g protein of a mixed protein powder (Whey/Casein)
  • 1Tbsp Peanut butter

Dinner

  • 8 oz. Steak (or salmon or other fish, or chicken or other poultry, or pork)
  • 2 cups mixed green Salad
  • 2 Tbsp salad dressing (olive oil n vinegar)

Snack (within 8 hours from when you consumed post-workout meal)

  • 20-30 g protein from a mixed protein powder (Whey/Casein)
  • or 1 cup cottage cheese or 1 cup Greek yogurt (with 1 teaspoon honey)
  • 1 Tbsp Peanut butter (can add to shake or Greek yogurt or eat separate)

Sample IF meal plan for those working out at lunchtime:

Pre-workout 1 (30 minutes before workouts; this starts your 8-hour feeding window)

  • 5-10 grams BCAAs
  • 2-5 grams creatine (depending on form)
  • 2-3 grams beta-alanine
  • 1-2 grams betaine
  • 20-30 g protein from a mixed protein powder (Whey/Casein)

Post-workout (within 30 minutes after workouts)

  • 20-40 g protein from a mixed protein powder (Whey/Casein)
  • 5-10 grams BCAAs
  • 2-5 grams creatine (depending on form)
  • 2-3 grams beta-alanine
  • 1-2 grams betaine
  • 2 grams L-carnitine or L-carnitine L-tartrate
  • 2-5 grams glutamine

Breakfast (30-60 minutes after pos-tworkout meal)

  • 20-30 g protein of a mixed protein powder (Whey/Casein)
  • 3 whole eggs
  • 3 egg whites
  • 1 Tbsp Olive oil

(scramble eggs cook in olive oil)

Late-morning snack

  • 1 cup low-fat cottage cheese

Lunch

  • 6 oz. can albacore tuna
  • 2 cups mixed green Salad
  • 1 Tbsp salad dressing (olive oil n vinegar)

(add tuna to salad)

Afternoon Snack

  • 20-30 g protein of a mixed protein powder (Whey/Casein)
  • 1Tbsp Peanut butter

Dinner

  • 8 oz. Steak (or salmon or other fish, or chicken or other poultry, or pork)
  • 2 cups mixed green Salad
  • 2 Tbsp salad dressing (olive oil n vinegar)

Snack (within 8 hours from pre-workout meal)

  • 20-30 g protein from a mixed protein powder (Whey/Casein)
  • or 1 cup cottage cheese or 1 cup Greek yogurt (with 1 teaspoon honey)
  • 1 Tbsp Peanut butter (can add to shake or Greek yogurt or eat separate)

Sample meal plan for those working out after work/before dinner:

Breakfast (This starts your 8-hour feeding window so have this 8 hours before you plan on having your last meal)

  • 20-30 g protein of a mixed protein powder (Whey/Casein)
  • 3 whole eggs
  • 3 egg whites
  • 1 Tbsp Olive oil

(scramble eggs cook in olive oil)

Late-morning snack

  • 1 cup low-fat cottage cheese

Lunch

  • 6 oz. can albacore tuna
  • 2 cups mixed green Salad
  • 2 Tbsp salad dressing (olive oil n vinegar)

(add tuna to salad)

Afternoon Snack

  • 20-30 g protein of a mixed protein powder (Whey/Casein)
  • 1Tbsp Peanut butter

Pre-workout 1 (30-45 minutes before workouts)

  • 5-10 grams BCAAs
  • 2-5 grams creatine (depending on form)
  • 2-3 grams beta-alanine
  • 1-2 grams betaine
  • 20-30 g protein from a mixed protein powder (Whey/Casein)

Post-workout (within 30 minutes after workouts)

  • 20-40 g protein from a mixed protein powder (Whey/Casein)
  • 5-10 grams BCAAs
  • 2-5 grams creatine (depending on form)
  • 2-3 grams beta-alanine
  • 1-2 grams betaine
  • 2 grams L-carnitine or L-carnitine L-tartrate
  • 2-5 grams glutamine

Dinner (30-60 minutes after post-workout meal)

  • 8 oz. Steak (or salmon or other fish, or chicken or other poultry, or pork)
  • 2 cups mixed green Salad
  • 2 Tbsp salad dressing (olive oil n vinegar)

Snack (within 8 hours of breakfast)

  • 20-30 g protein from a mixed protein powder (Whey/Casein)
  • or 1 cup cottage cheese or 1 cup Greek yogurt (with 1 teaspoon honey)
  • 1 Tbsp Peanut butter (can add to shake or Greek yogurt or eat separate)

Sample meal plan for those working out at night after dinner:

Breakfast (This starts your 8-hour feeding window so have this 8 hours before you plan on having your last meal)

  • 20-30 g protein of a mixed protein powder (Whey/Casein)
  • 3 whole eggs
  • 3 egg whites
  • 1 Tbsp Olive oil

(scramble eggs cook in olive oil)

Late-morning snack

  • 1 cup low-fat cottage cheese

Lunch

  • 6 oz. can albacore tuna
  • 2 cups mixed green Salad
  • 2 Tbsp salad dressing (olive oil n vinegar)

(add tuna to salad)

Snack

  • 20-30 g protein of a mixed protein powder (Whey/Casein)
  • 1Tbsp Peanut butter

Dinner

  • 8 oz. Steak (or salmon or other fish, or chicken or other poultry, or pork)
  • 2 cups mixed green Salad
  • 2 Tbsp salad dressing (olive oil n vinegar)

Pre-workout 1 (30-45 minutes before workouts)

  • 5-10 grams BCAAs
  • 2-5 grams creatine (depending on form)
  • 2-3 grams beta-alanine
  • 1-2 grams betaine
  • 20-30 g protein from a mixed protein powder (Whey/Casein)

Pos-tworkout (within 30 minutes after workouts)

  • 20-40 g protein from a mixed protein powder (Whey/Casein)
  • 5-10 grams BCAAs
  • 2-5 grams creatine (depending on form)
  • 2-3 grams beta-alanine
  • 1-2 grams betaine
  • 2 grams L-carnitine or L-carnitine L-tartrate
  • 2-5 grams glutamine

Before Bed Snack (within 8 hours of breakfast)

  • 20-30 g protein from a mixed protein powder (Whey/Casein)
  • or 1 cup cottage cheese or 1 cup Greek yogurt (with 1 teaspoon honey)
  • 1 Tbsp Peanut butter (can add to shake or Greek yogurt or eat separate)

References:
Pilegaard, H., et al. Effect of short-term fasting and refeeding on transcriptional regulation of metabolic genes in human skeletal muscle. Diabetes 52:657-662, 2003.

Hildebrandt, Exercise attenuates the fasting-induce transcriptional activation of metabolic genes in skeletal muscle. Am J Physiol Metab 278:E1078-E1086, 2000.

Mattson, M. P. and Wan, R. Beneficial effects of intermittent fasting and caloric restriction on the cardiovascular and cerebrovascular systems. J Nutr Biochem. 2005 Mar;16(3):129-37.

Carlson, A. J. and Hoelzel, F. Apparent prolongation of the life span of rats by intermittent fasting. J Nutr. 1946 Mar;31:363-75.

Stote, K. S., et al. A controlled trial of reduced meal frequency without caloric restriction in healthy, normal-weight, middle-aged adults. Am J Clin Nutr 85:981-988, 2007.

Trabelsi, K., et al. Effects of Ramadan fasting on biochemical and anthropometric parameters in physically active men. Asian Journal of Sports Medicine 2(3):134-144, 2011.