It is New Year's resolution time and
one of the perennial resolutions
for many Americans is, "this year I
am going to lose weight and keep
it off."
Literally two thirds of Americans
are overweight or worse, so there are a lot
of such resolutions being made. Like gym
memberships, however, there are far more
resolutions initially undertaken than followed
through. Nevertheless, this time around
things can be different. One key is that the
weight loss strategy adopted should also
be one that can be continued as a normal
everyday diet pattern. There is no reason that
this should not work as long as realistic goals
are adopted. Life, as the observation goes, is
a marathon, not a sprint. Moderate, yet well
thought-out changes in the diet regarding
the ratios of protein, carbohydrate and fat
can yield durable results over a span of three
to six months. Similarly, care in terms of the
timing of food intake, consumption of fiber
and phytonutrients, and so can yield big
rewards.
High Protein Beats High Carbohydrate During Weight Loss
Let's start with the initial weight loss goal.
Ads for diet products and programs often
promise "ten pounds in ten days," but such
promises, even were they true, are never
lasting. The body resists extreme changes
and, in the end, the body always wins. A
better approach is to coax the body in the
desired direction so that it becomes more
metabolically flexible and thus can burn
fat for energy rather than storing it. This
means overcoming roadblocks such as poor
blood sugar control dieting-induced loss of lean tissue. The
protein-to-carbohydrate make-up of meals is important here.
Indeed, this ratio and not the amount of fat in the diet is
determining.
Realistically, reducing energy intake by approximately
500 calories per day is sufficient for many dieters initially
to experience weight loss of 1 – 2 pounds per week. The
catch is that weight loss based only on restricting calories
has a poor record for improving impaired glucose tolerance
and typically leads to a loss of the more actively calorie-metabolizing
lean body tissues. A study with obese subjects
published in the journal BMJ Open Diabetes Res Care
demonstrates that this need not be the outcome of dieting.1
One hundred percent of obese adults using a high protein
(HP) moderately calorically-restricted diet, but not those on
a similarly restricted high carbohydrate (HC) diet achieved
a return to normal glucose tolerance in addition to benefits
in their markers for cardiovascular and inflammatory health.
On the HP diet there was an increase in the percentage of
lean body mass and a decrease in the percentage of fat body
mass with weight loss whereas the HC diet led to a decrease
in the percentage of lean body mass along with a decrease
in the percentage of fat body mass. The change in glucose
tolerance/blood sugar levels and the improvement in the
percent lean body mass demonstrated with higher protein
intake and restricted carbohydrate intake are highly desirable outcomes. The key was substituting protein for carbohydrate
calories.
For this study, researchers randomized 24 women and
men with elevated fasting glucose levels in the pre-diabetic
range to either a HP diet (30 percent protein, 30 percent
fat, 40 percent carbohydrate; n=12) or a HC diet (15 percent
protein, 30 percent fat, 55 percent carbohydrate; n=12)
for a study lasting six months. All meals were provided to
these subjects for the six months. At the start of the study
and at its conclusion, tests were performed to determine
oral glucose tolerance and serum insulin levels as well as
a variety of other parameters indicative of metabolism and
inflammation. X-ray scans were conducted to determine
body composition in terms of the percentage
of lean and fat tissue.
The differing diets led to dramatically
different results. According to the authors
of the paper, on the HP diet 100 percent
of the subjects exhibited remission of their
pre-diabetes to normal glucose tolerance
whereas only 33.3 percent of subjects on the
HC diet exhibited this remission. Moreover,
the high protein arm subjects exhibited
significant improvement in (1) insulin
sensitivity (p=0.001), (2) cardiovascular risk
factors (p=0.04), (3) inflammatory cytokines
(p=0.001), (4) oxidative stress (p=0.001),
and (5) increased percent lean body mass
(p=0.001) compared with the HC diet.
In terms of the findings likely to be of
particular interest to most dieters, it should
be pointed out again there was an increase
in the percentage of lean body mass and
decrease in the percentage of fat body mass
with weight loss on the HP diet. In contrast,
there was a decrease in the percentage of
lean body mass with weight loss on the HC
diet although the percentage of fat body mass
did decline as expected. Importantly, both
metabolic parameters and inflammation
markers were improved only on the high
protein / reduced carbohydrate, moderately
calorically restricted diet.
Doesn't Eating Fat Make You Fat?
Keeping weight off after a diet is the real
challenge. The fact that in dieting it is
mostly the caloric restriction that leads to
weight loss and not diet specifics has been
known for decades.2 For instance, in 1996
a study was published that compared diets
much more disparate than the one described above.3 Forty-three
obese adults were randomly assigned to receive diets
containing 1,000 calories/day composed of either 32 percent
protein, 15 percent carbohydrate, and 53 percent fat or 29
percent protein, 45 percent carbohydrate, and 26 percent
fat. There was no significant difference in the amount of
weight lost. Nevertheless, just as in the study above, fasting
plasma glucose, insulin, cholesterol, and triacylglycerol
concentrations decreased significantly in patients eating
low-energy diets that contained 15 percent carbohydrate, but
neither plasma insulin nor triacylglycerol concentrations fell
significantly in response to the higher carbohydrate diet.
A more recent study looked at moderate energy intake on a very high-fat, low-carbohydrate (73
percent of energy from fat, 10 percent of energy
from carbohydrate and 17 percent of energy
from protein) or low-fat, high-carbohydrate (30
percent of energy from fat, 53 percent of energy
from carbohydrate and 17 percent of energy
from protein) diet for 12 weeks.4 Unlike most
modern diets, these were diets involving only
minimally processed carbohydrates and fats.
Despite expectations, the high fat diet did not
raise LDL cholesterol; however, it did raise HDL
cholesterol. According to one of the co-authors
of the study, "the very high intake of total and
saturated fat did not increase the calculated risk
of cardiovascular diseases." "Participants on
the very-high-fat diet also had substantial improvements
in several important cardiometabolic
risk factors, such as ectopic fat storage,
blood pressure, blood lipids (triglycerides),
insulin and blood sugar."5
Therapeutic diets usually restrict either
carbohydrates or fats. If fats are restricted,
then the diet will tend towards an increased
protein content. Most dieters will find that in
the early stages, this high intake of protein will
reactivate the thyroid and make life easier. There
is plenty of clinical evidence to the effect that
high protein snacks reduce calorie intake more
than do snacks of carbohydrate, fat or alcohol
for overweight individuals accustomed to the
usual American mixed diet. And increasing
protein intake to 25 percent of calories clinically
has been demonstrated to increase both weight
loss (by 75 percent) and fat loss (by 57 percent)
more than was found on a protein intake of 12
percent. Still, eating protein is not a panacea
(too much is too much6) and protein needs
to be matched with goodly intakes of fruit and
vegetables as well as the avoidance of refined carbohydrates
for best results. Moreover, decades of research, as indicated
above, demonstrates that carbohydrates need to be replaced
by protein for best results.
Does Gut Bacteria Play a Role in Weight Regain?
Preserving lean tissue and improving various metabolic
parameters certainly help to make dieting results more stable
and lasting. An additional factor, one seldom considered, is
the role of gastrointestinal bacteria in weight maintenance.
Human experiments have demonstrated that changing
the diet to artificially induce blood sugar regulation issues
surprisingly quickly results in changes in the gut microbiome
that cause these bacteria to release more calories from food
than normally would be the case, for instance, by digesting
supposedly indigestible fiber. Similarly, it is well established
that individuals who are overweight, obese and/or diabetic
often have substantially different gut microflora than
individuals who are lean.7 Therefore, so-called yo-yo dieting
and recurrent obesity might be at least influenced by the
microbes found in the gut.
A recent report in Nature casts further light on an
aspect of this issue.8 As observed by one of the authors,
Dr. Eran Elinav from the Weizmann Institute of Science in
Israel, "we've shown in obese mice that following successful
dieting and weight loss, the microbiome retains a 'memory' of previous obesity." Co-author Professor Eran Segal
elaborated, "this persistent microbiome accelerated the
regaining of weight when the mice were put back on a high-calorie
diet or ate regular food in excessive amounts." One of
the findings of this research is that the post-diet gut biome
destroys certain flavonoids from the diet that influence
energy metabolism. This interferes with energy release from
fat. In post-dieting mice this leads to an accumulation of
extra fat when they are returned to a higher-calorie diet.
Experimentally, according to the paper, "flavonoid-based
'post-biotic' intervention ameliorates excessive secondary
weight gain." This suggests that microbiome-targeting
approaches may help with weight regain.
Putting It Together
Diets similar to the 30 percent protein, 30 percent fat,
40 percent carbohydrate diet described above have been
proposed for several decades.9 In addition, the role of
phytonutrients now is strongly supported. Both these aspects
of good meal planning need to be addressed. A simple
approach to meals is to make sure that roughly one third
of the plate is covered with a protein source and one half or
even two thirds of the meal plate is covered with the lightly
cooked vegetable of your choice (salad does not count here;
corn and carrots are counted as carbohydrates). Always eat
this vegetable serving, which should be at least two cups
of vegetables. Eat protein before eating any carbohydrates
in the main meal for better digestion and better appetite
control. (Classic European, Chinese and Japanese meal
planning often arranges protein courses before carbohydrate
courses.) Remember that vegetables are perfectly good
carbohydrate sources and may well be consumed in the
place of concentrated carbohydrates, such as rice and
potatoes. Dieters also should consider supplementing with
probiotics in conjunction with prebiotics. Finally, as noted
in previous TotalHealth articles, when meals are eaten may
be as important and what is eaten; never skip breakfast and
avoid eating late in the evening or before bedtime.10
References
- 1. Stentz FB, Brewer A, Wan J, Garber C, Daniels B, Sands C, Kitabchi AE. Remission of pre-diabetes to normal glucose tolerance in obese adults with high protein versus high carbohydrate diet: randomized control trial. BMJ Open Diabetes Res Care. 2016 Oct 26;4(1):e000258.
- 2. Sacks FM, Bray GA, Carey VJ, Smith SR, Ryan DH, Anton SD, McManus K, Champagne CM, Bishop LM, Laranjo N, Leboff MS, Rood JC, de Jonge L, Greenway FL, Loria CM, Obarzanek E, Williamson DA. Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates. N Engl J Med. 2009 Feb 26;360(9):859–73.
- 3. Golay A, Allaz AF, Morel Y, de Tonnac N, Tankova S, Reaven G. Similar weight loss with low- or high-carbohydrate diets. Am J Clin Nutr. 1996 Feb;63(2):174–8.
- 4. Veum VL, Laupsa-Borge J, Eng Ø, Rostrup E, Larsen TH, Nordrehaug JE, Nygård OK, Sagen JV, Gudbrandsen OA, Dankel SN, Mellgren G. Visceral adiposity and metabolic syndrome after very high-fat and low-fat isocaloric diets: a randomized controlled trial. Am J Clin Nutr. 2016 Nov 30. pii: ajcn123463. [Epub ahead of print]
- 5. University of Bergen. "Saturated fat could be good for you, study suggests." ScienceDaily. ScienceDaily, 2 January 2017. www.sciencedaily.com/releases/2016/12/161202094340.htm.
- 6. Rietman A, Schwarz J, Tomé D, Kok FJ, Mensink M. High dietary protein intake, reducing or eliciting insulin resistance? Eur J Clin Nutr. 2014 Sep;68(9):973–9.
- 7. Zhang Q, Wu Y, Fei X. Effect of probiotics on body weight and body-mass index: a systematic review and meta-analysis of randomized, controlled trials. Int J Food Sci Nutr. 2015 Aug;67(5):571–80.
- 8. Thaiss CA, Itav S, Rothschild D, Meijer M, Levy M, Moresi C, Dohnalová L, Braverman S, Rozin S, Malitsky S, Dori-Bachash, M. Kuperman Y, Biton I, Gertler A, Harmelin A, Shapiro H, Halpern Z, Aharoni A, Segal E, Elinav E. Persistent microbiome alterations modulate the rate of post-dieting weight regain. Nature. 2016 Nov 24. doi:10.1038/nature20796.
- 9. Sears B, Ricordi C. Anti-inflammatory nutrition as a pharmacological approach to treat obesity. J Obes. 2011;2011.
- 10. Sellix MT. For Management of Obesity and Diabetes: Is Timing the Answer? Endocrinology.2016 Dec;157(12):4545–9.