CLAIM #4: Drinking Water Boosts Your Metabolism

This is entry #4 in a 9-part series on Metabolic Myths.

Metabolism-boosting hype generally has a grain of truth behind it that has been way overblown. In other cases, long disproved theories continue to be touted because they are super effective as click-bait (or selling books). You rarely see any actual numbers -- how many calories per day will this raise my resting metabolic rate? -- attached to claims. That’s because for the most part the actual increase (if any) in resting metabolic rate (or other components of your daily total energy expenditure), is too small to be of any practical significance.

Metabolism mythology has a life of its own though as it gets regurgitated and reposted throughout the internet and fad-diet books (and unfortunately even by many otherwise reputable sources).

Review "Metabolism" here: Metabolic Rate

My last topics were eating more frequently, muscle and breakfast, today's topic is water:

CLAIM: drinking water (or especially cold water) increases your metabolic rate.

Three semi-recent studies reported that drinking cold water increased metabolic rate by 24- to 30%.i ii iii These studies involved 500-ml (16.9-oz.) of cold water, and the increase in metabolic rate after drinking lasted about 60 minutes.

The author of one of these papersⁱⁱ concluded that, drinking 2 liters (67-oz.) of water per day would augment resting energy expenditure (REE) by approximately 95-calories.

Stunned by these extraordinary results (compared to data from previous studies), several researchers set up their own new studies. Brown (2006)iv found that cold water increased REE by only about 5%, while room temperature water had no effect. Girona (2014)v tested the metabolic response to drinking cold, room temperature, and body-temperature water. Cold and room temperature water increased REE by 2.9% and 2.3% over 90 mins. And most recently, Charriere (2015)vi tested drinking (room temperature) water against “sham drinking” (raising a glass of water to the lips pretending to drink, but not drinking). The water drinking led to a marginal (2.7%) increase in REE, but the result was not a statistically significant difference from the response to sham drinking (1.5%).

In summary, the vast majority of studies have found a tiny (if any) increase in REE from water drinking (0- to <5%).iv vi vii Furthermore, the non-significant differences found between drinking cold, or room-temperature water, and “sham-drinking” (pretending to drink the glass of water), calls into question whether water-drinking itself is actually even the variable affecting REE.vi

Just for fun, let's shift to considering the tiny bump in REE that some studies showed. What is the most that bump in REE could add up to?

For 40-year-old, 166-lb. female with an average REE (1,421-kcals) a 5% increase in REE (that lasts for 60-minutes), adds up to just 1.75-calories.

Remember this is for drinking 500 ml (16.9-oz.) of water. For 2 liters of water the bump would add up to 7-calories, which is equivalent to a scant half-teaspoon of sugar.

So while technically it might be argued that drinking water can increase REE, in fact—once again—we have a metabolic myth that has no practical significance.

In closing it's important to note that there's absolutely nothing that's healthier for you to drink, than water. As I've written about before (Is what you're drinking helping...), most people don't drink enough water, and should choose their beverages more carefully.

If you read this far and wondered why I didn't touch on the purported "fat-burning" effects of water it's just because this blog is already too long! I have it on my calendar for 2018 though, so check back from time to time.

All the Best!
Dorene

Related articles:
Is what you're drinking helping or hindering your weight loss efforts?
Media Fail: Busting the water "Myth"

References:

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[i] Influence of water drinking on resting energy expenditure in overweight children. Dubnov-Raz, et al. Intl J Obes 2011;35(10):1295-1300.

[ii] Water-induced thermogenesis. Boschmann, et al. J Clin Endocrinol Metab 2003;88(12):6015-9.

[iii] Water Drinking Induces Thermogenesis through Osmosensitive Mechanisms. Boschmann, et al. J Clin Endocrinol Metab 2007;92(8):3334-3337.

[iv] Water-Induced Thermogenesis Reconsidered: The Effects of Osmolality and Water Temperature on Energy Expenditure after Drinking. Brown, et al. J Clin endocrinol Metab 2006;91:2598-3602.

[v] Cardiovascular and metabolic responses to tap water ingestion in young humans: does the water temperature matter? Girona, et al. Acta Physiologica 2014;211(2):358-370.

[vi] Water-induced thermogenesis and fat oxidation: a reassessment. Charriere, et al. Nutr Diabetes 2015;5:e190.

[vii] Negative, Null and Beneficial Effects of Drinking Water on Energy Intake, Energy Expenditure, Fat Oxidation and Weight Change in Randomized Trials: A Qualitative Review. Stookey, JD. Nutrients 2016;8(1):19.

Claim #3: Eating More Frequently Boosts Your Metabolism

This is entry #3 in a 9-part series on Metabolic Myths.

Metabolism-boosting hype generally has a grain of truth behind it that has been way overblown. In other cases, long disproved theories continue to be touted because they are super effective as click-bait (or selling books). You rarely see any actual numbers -- how many calories per day will this raise my resting metabolic rate? -- attached to claims. That’s because for the most part the actual increase (if any) in resting metabolic rate (or other components of your daily total energy expenditure), is too small to be of any practical significance.

Metabolism mythology has a life of its own though as it gets regurgitated and reposted throughout the internet and fad-diet books (and unfortunately even by many otherwise reputable sources).

Review "Metabolism" here: Metabolic Rate

My last topics were muscle and breakfast, today's topic is eating-more-frequently:

CLAIM: Eating More Frequently will Boost Your Metabolism

The notion that eating more often was conducive to lower body weights got started in the 1960s when researchers noticed higher body weights were correlated with fewer eating occasions in epidemiological studies. However, the self-reported energy intakes in those kinds of studies was long ago shown to be flawed and unreliable. Since then randomized controlled trials have shown what would be expected, that total daily energy intake increases along with the number of eating occasions per day—not the opposite.[i]

Despite this, dieting advice encouraging a more frequent eating pattern of smaller meals continues to be propagated. One popular claim is that this pattern raises for metabolism.

Despite the fact that digesting and assimilating what you eat DOES burn calories, it does NOT affect your underlying metabolic rate. By definition the thermic effect of food (TEF) is the measured energy expenditure above Resting Metabolic Rate (RMR) in response to eating.

TEF averages 10% of calories consumed for “mixed” meals (combinations of protein, carbohydrate and fat). The number one determinate of TEF is calories. For a given number of calories TEF remains the same whether those calories are divided into 3-meals, 6-meals, or eaten all at once.[ii]

A related theory behind advice to eat more often, is that eating more often would decrease hunger and increase satiety so that people would avoid overeating “later.”

Studies investigating this theory keep total calorie intake the same, and lean toward showing that larger-meals are more satisfying than smaller meals.[iii] With a full-sized meal you have the physical sense that you've eaten “enough,” versus a snack-size-meal that doesn't have enough volume or energy for your body to register physical or psychological satisfaction.[iv]

Another interesting thread to this area of research is the effect of irregular meal patterns (random snacking) on blood glucose, insulin sensitivity and appetite related hormones. Our bodies aclimtize to, and function best, with a regular meal pattern.[v][vi]

It's important also to point out that when you reduce your energy intake to promote weight loss, your remaining calorie allotment may not be enough to create filling meals and snacks. On the other hand, when eating to maintain your weight your calorie allotment stretches further providing more flexibility.

If you get hungry between meals, the first thing you need to do is evaluate exactly what you’re eating that fails to keep hunger-at-bay until the next meal? The problem is most likely the combined issues of: a) too much sugar and/or refined carbohydrates, and b) not enough protein. Shoot for 25- to 30-grams of protein at each of your main meals, and choose more nutrient-dense whole foods. Then (assuming each meal also provides adequate calories) you shouldn’t feel hunger before it’s “time-to-eat” again.

It's perfectly fine to snack between meals if you prefer that pattern (and can do it within your calorie allowance). There's no benefit, however, to changing to a snacking pattern if you're not a snacker. Whether your goal is weight loss or not the majority of your snacks should ideally be healthy choices that help you meet your nutrient requirements for the day.

The bottom line: Suggestions that eating smaller more frequent meals will increase your metabolsim are simply false. Dividing your calories between more meals does NOTHING to increase your underlying (or total) metabolism. That's good news, you can stick to whatever pattern that you've found works best for you be it snacky or not.

All the best,
-Dorene

References:

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[i] The impact of daily meal pattern on energy Balance. Bellisle, F. Scan J Nutr 2004;38(3):114-118.

[ii] The Energy Content and Composition of Meals Consumed after an Overnight Fast and Their Effects on Diet Induced Thermogenesis: A Systematic Review, Meta-Analyses and Meta-Regressions. Quatela, et al. Nutrients 2016;8(11)670.

[iii] The Effect of Eating Frequency on Appetite Control and Food Intake: Brief Synopsis of Controlled Feeding Studies. Leidy and Campbell. J Nutr 2011;141:154s-157s.

[iv] Evidence for Efficacy and Effectiveness of Changes in Eating Frequency for Body Weight Management. Kant, AK. Adv Nutr 2014;(5):822-828.

[v] Association between eating frequency, weight, and health. Palmer, et al. Nutr Reviews 2009;67(7):379-390.

[vi] When to eat and how often? Parks and McCrory. Am J Clin Nutr. 2005;81:3-4.

Claim#2: Adding Muscle Boosts Your Metabolism

This is entry #2 in a 9-part series on Metabolic Myths.

Metabolism-boosting hype generally has a grain of truth behind it that has been way overblown. In other cases, long disproved theories continue to be touted because they are super effective as click-bait (or selling books). You rarely see any actual numbers -- how many calories per day will this raise my resting metabolic rate? -- attached to claims. That’s because for the most part the actual increase in resting metabolic rate (or other components of your daily total energy expenditure), is too small to be of any practical significance.

Metabolism mythology has a life of its own though as it gets regurgitated and reposted throughout the internet and fad-diet books (and unfortunately even by many otherwise reputable sources).

Review "Metabolism" here: Metabolic Rate

My last topic was breakfast, today's topic is muscle:

CLAIM: Adding muscle boosts your metabolism or aids in weight loss

Muscle burns more than fat (at rest) so adding muscle will (technically) increase your resting metabolic rate.

It's not that simple, however. Following are two points that essentially throw cold water on this oversimplification.

1) You can't actually ADD muscle while losing weight. The best you can do -- if weight loss is your goal -- is to minimize the loss of skeletal muscle over the weight loss process. The back-story is that when you gain weight you gain both lean body mass (LBM; i.e. muscle) and fat mass (FM)... and then in reverse, when you lose weight, you tend to lose about the same ratio that you gained. The two major factors that impact your change in LBM are actually a) the magnitude of energy deficit you're in, and b) the protein content of your diet.[1][2][3] You need a minimum of 1.2-grams of protein per/kg (2.6-grams/pound) of your body weight to minimize loss of LBM.[4][5][6]

2) Improving your body composition has an insignificant effect on your resting metabolic rate.

If weight loss isn't your goal and you just want to improve your body composition, what could you expect as a good outcome from a strength training program?

Let’s say you engaged in a regular strength training program (spending 120- to 180-minuets per week) for a few months and gained 5 pounds of muscle while also losing 5 pounds of fat. This would be a huge achievement, and a result that a small minority of exercisers are consistent enough to achieve.[7] At the end of the day, the net increase in your resting metabolic rate would be just 19.5 calories per day.

Why so little? Both skeletal muscle and fat (adipose tissue) have low resting metabolic rates (5.9 and 2-calories per pound respectively).[8] The type of muscle (lean body mass) that does burn a lot of calories at rest is organ tissue (heart, brain, kidneys, etc.).[8][9] Strength training won’t increase organ mass.

Here's the math:

[(5-lbs. muscle x 5.9 = 29.5) - (5-lbs. fat x 2 = 10) = 19.5]

That is an increase, but it has no practical significance.

Thankfully, there is some good news.

You will have lost inches from your waist and/or hips, and you will feel better. In fact strength training has been shown to lower (systolic and diastolic) blood pressure, improve insulin resistance, lower LDL-(bad)cholesterol and triglycerides, and raise HDL-(good)cholesterol.[4] Your self-esteem might even be higher.

Strength training clearly has many benefits, but for the average Joe or Jane (who wants to lose weight), increasing your resting metabolic rate isn’t one of them.

While the best advice is that you try to limit your loss of muscle while you lose weight, it's important to understand that your "metabolic rate" will always be smaller when you are smaller!

Sorry, but it is what it is!

All the best!
-Dorene

References:

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[1] Weight Loss Composition is One-Fourth Fat-Free Mass: A Critical Review and Critique of This Widely Cited Rule. Heymsfield, et al. Obes Rev 2014;15(4):310-321.

[2] Lean Body Mass-Body Fat Interrelationships in humans. Forbes, GB. Nutr Rev 1987;45(8):225-231.

[3] Body Fat and Fat-Free-Mass Interrelationships: Forbes' Theory Revisited. Hall, KD. Br J Nutr. 2007;97(6):1059-1063.

[4] American College of Sports Medicine Position Stand. Appropriate Physical Activity Intervention Strategies for Weight Loss and Prevention of Weight Regain for Adults. Donnelly, et al. Med Sci Sport Exercise 2009;41(2):459-471.

[5] The role of protein in weight loss and maintenance. Leidy, et al. Am J clin Nutr 2015;101(suppl):1320s-1329s.

[6] Exploration of protein requirement during weight loss in obese older adults. Weijs and Wolfe. Clin Nutr 2016;35(2):394-398.

[7] Body composition in sport and exercise: directions for future research. Wilmore, JH. Med Sci Sport Exerc 1983;15(1):21-31.

[8] Specific metabolic rates of major organs and tissues across adulthood: evaluation by mechanistic model of resting energy expenditure. Wang, et al. Am J Clin Nutr 2019;92:1369-77.

[9] Elia M: Organ and Tissue Contribution to Metabolic Rate, In: Kinney J, Tucker HN (eds). Energy Metabolism: Tissue Determinants and Cellular Corollaries. New York, NY: Raven Press, Ltd.; 1992:61-79.

CLAIM #1: Breakfast Boosts Your Metabolism... (#1 of 9 "Boost Your Metabolism" Claims that are Actually False)

Metabolism-boosting hype generally has a grain of truth behind it that has been way overblown. In other cases, long disproved theories continue to be touted because they are super effective as click-bait (or selling books). You rarely see any actual numbers -- how many calories per day will this raise my resting metabolic rate? -- attached to claims. That’s because for the most part the actual increase in resting metabolic rate (or other components of your daily total energy expenditure), is too small to be of any practical significance.

Metabolism mythology has a life of its own though as it gets regurgitated and reposted throughout the internet and fad-diet books (and unfortunately even by many otherwise reputable sources).

Each of the following false and misleading "Boost Your Metabolism" topics will be discussed in a separate blog over the next couple weeks (not necessarily in this order): Breakfast, Build Muscle, Meal Frequency, Water, Cheat Meals, EPOC, Hot Peppers, MCTs, and Eating after 7pm.

Myth #1: Breakfast boosts your metabolism.

Claims and advice that eating breakfast in some way promotes weight management continue to be doled out despite a lack of evidential support.[i] This problem is so pervasive that it was the topic of a 2013 scientific paper (by highly respected researchers from University of Alabama at Birmingham's NIH-funded Nutrition Obesity Research Center) basically admonishing the scientific community for biased research, and calling on it to do better.[ii]

Some of the false claims regarding breakfast:

CLAIM: Your metabolism will be higher all day if you start with breakfast

The FACTs: the metabolic response to eating breakfast is not different than that to eating food at any time later in the day.[iii] Digesting and assimilating what you eat is called the thermic effect of food (TEF), and by definition TEF is measured as the energy expenditure above resting metabolic rate in response to eating.[iv] [v]

CLAIM: Skipping breakfast leads to overeating later in the day.

The FACTs:  When breakfast is omitted from the daily meal pattern (skipped) calorie intake at the end of the day is generally lower. In other words, the calories missed at breakfast are not completely offset by eating more at lunch or dinner. So at the end of the day an energy deficit remains.

CLAIM: Skipping breakfast makes you hungry.

The FACTs: The effect of breakfast on satiety is transient and not more advantageous than the next meal of the day provides independent of breakfast.[iv]  Note however, that habitual breakfast-eaters and habitual breakfast-skippers respond differently. That's because your body adjusts to the pattern you usually follow so that it "expects," that pattern. So if you usually eat breakfast, and you try skipping it you’re going to be extra hungry for lunch. On the other hand, breakfast skippers aren’t hungry for breakfast to begin with, and eating breakfast is like a curve ball disrupting their system in a different way (which may be why some people claim that eating breakfast makes them more hungry).

Evidence (from well done randomized controlled trials) does seem to show:

• That breakfast eaters may have higher morning physical activity levels (via less sitting/more moving around) compared to breakfast skippers.[vi]
• People who regularly eat breakfast tend not to be night eaters, so they are hungry when they get up.
• Habitual breakfast eaters also tend to be non-smokers, consume less fat and alcohol but more fiber and micronutrients, and are more physically active.[vii]

Clearly, trying to attribute differences in BMI between breakfast eaters, or skippers, is not a straightforward endeavor.

It is important to note that for diabetics eating breakfast results in lower insulin and blood glucose levels for the rest of the day. So, it is very important that diabetics eat breakfast.

For everybody else, you can stick with what works for you because eating breakfast does NOT increase your (resting) metabolism, improve appetite regulation, or reduce overall energy intake. TEF from breakfast is no different, and provides no advantage over, the TEF from any other meal.

The problem with boost-your-metabolism myths is that they distract you from focusing on what actually works, and propagate the notion that there are simple tricks or magical methods that promote weight loss. The best advice remains to be: eat a healthy diet, but not too much, and make activity a part of your day.

All the best!
-Dorene

References:

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[i] Meal skipping and variables related to energy balance in adults: a brief review, with emphasis on the breakfast meal. McCrory, MA. Physiol Behav 2014;134:51-54.

[ii] Belief beyond the evidence: using the proposed effect of breakfast on obesity to show 2 practices that distort scientific evidence. Brown, et al. Am J Clin Nutr 2013;98:1298-1308.

[iii] The Energy Content and Composition of Meals Consumed after an Overnight Fast and Their Effects on Diet Induced Thermogenesis: A Systematic Review, Meta-Analyses and Meta-Regressions. Quatela, et al. Nutrients 2016;8(11)670.

[iv] The effect of breakfast on appetite regulation, energy balance and exercise performance. Clayton and Lewis. Proc Nutr Soc 2016;75(3):319-327.

[v] Effect of breakfast skipping on diurnal variation of energy metabolism and blood glucose. Kobayashi, et al. Obes Res Clin Prac 2014;8(3):e201-98.

[vii] The effectiveness of breakfast recommendations on weight loss: a randomized controlled trial. Dhurandhar et al. Am J Clin Nutr 2014;100:507–13.

[viii] The causal role of breakfast in energy balance and health: a randomized controlled trial in lean adults. Betts, et al. Am J Clin Nutr 2014;100:539-547.

Protein and the Thermic Effect of Food

The Thermic Effect of Food (TEF) is one of the three major components of daily energy expenditure, the other two components being a) Basal Metabolic Rate and b) the energy cost of activity.  

The energy expenditure from TEF is related to the stimulation of obligatory energy-requiring processes associated with eating, digesting, absorbing, and storing food (as well as the facultative energy expenditure associated with hormone secretion, sodium-potassium ATPase pump activity, protein synthesis, and substrate recycling).

The TEF raise in metabolism spikes after meals, and gradually declines over ~10 hours (as determined by the return to Basal Metabolic Rate). The main determinant of TEF is the total energy content of the meal (total calories consumed), followed by the protein fraction of the meal.

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