Are Low Carbohydrate Diets Best for Weight Loss?

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If you haven’t been bombarded with advertising for low carbohydrate foods, diets, plans and crazed anti-carbohydrate friends and coworkers in the past few years, you must be living on a remote island somewhere (taking any visitors?). The anti-carbohydrate, pro-fat crowd (including keto, Paleo, and Whole 30 – aka Paleo reinvented) devotees might be onto something. But that “something” isn’t a miraculous cure for obesity. Should you trade your low fat, higher carbohydrate diet for full fat foods and “bread” made from cauliflower and mozzarella cheese? It’s time to look past the media headlines to the latest research on low fat vs. low carbohydrate diets.

In this article I’ll cover:

  • the latest research on lower carbohydrate diets;
  • what this research means for you; and
  • a sidenote on the insulin hypothesis.

Should you switch to low carbohydrate vs. high carbohydrate foods?

The Latest Research on Low Carbohydrate Diets

In an attempt to determine which diet is best for weight loss, one of the latest studies collected and analyzed studies on low fat and low carbohydrate diets. A systematic review and meta-analysis, which combines the results of several studies, compared intervention studies > 1 year in length where participants were placed on low fat diets, low carbohydrate diets, other high fat dietary interventions or they continued eating whatever they wanted (their typical diet). Low fat diets ranged from  < 10% of calories from fat to < 30% of calories from fat. The diet interventions used ranged from providing instructions at the start of the study and expecting participants to follow the diet plan to regular counseling sessions with dietitians, food diaries and cooking lessons to actual feeding studies where participants were given most of their overall food intake (with the last approach the most well-controlled). Some studies coached participants to cut calories while others, including those put on low-carbohydrate Atkins-style diets, were told to eat until they were full without worrying about calories.

They analyzed results from 13 trials that examined weight maintenance as well as studies that didn’t include weight loss as a primary goal. In these studies low-fat and high-fat diets lead to a similar amount of weight loss. Low-fat diets were superior only when compared to the subjects’ normal diet – in other words actually going on a diet led to greater weight loss than not dieting (no surprise there). The tiebreaker came from an analysis of 35 weight loss trials, 29 of which were conducted using adults who were overweight, obese, or had type II diabetes. Overall, there was no difference between low-fat and high-fat diet interventions. Low-fat diets led to greater weight loss compared to groups who didn’t diet. However, higher fat diets were the clear winner (according to the headlines), leading to significantly greater weight loss after a year than low fat diets. Before tossing out your steel cut oatmeal, whole-grain bread and fresh Summer fruit, let’s take a closer look at this data. It was pulled from a comparison between low-fat diets and high-fat diets that varied by more than 5% of calories. So did low carbohydrate, higher fat diets really win or was it because subjects cut calories? Is it easier to cut calories on low carbohydrate, high fat diets? Participants on low carbohydrate diets lost about 2.2 pounds more weight after one year versus those on a low-fat diet. A 2.2-pound difference in weight loss after one year on a diet isn’t very impressive, especially considering many of the subjects were overweight or obese to begin with.

The End of Higher Carbohydrate, Low-Fat Diets?

Based on these results the authors suggest low-fat diets shouldn’t be the go-to recommendation for weight loss. However, the results of this study are mainly applicable to overweight, obese and type II diabetics – the primary populations examined in these studies. We can’t take the authors conclusion that low carbohydrate, higher fat diets are better if you are looking to lose a few pounds for a beach ready body. What works for an obese adult or type II diabetic will not necessarily work for an active adult who wants to get a 6-pack. Secondly, previous research shows low carbohydrate diets tend to produce greater weight loss, initially, than low fat diets (some of this is water weight since carbohydrates store 3-4 times their weight in water in the form of glycogen in muscles and the liver and your glycogen stores will start dropping when you drastically lower your carbohydrate intake) yet after a year, weight loss is equivalent between both diets. Other research shows weight loss over the first six months on a diet is the main predictor of both weight loss success and sticking to a diet over the long-term. Greater weight loss initially = better adherence = better success over time.

Long-term Success

What’s more disappointing than the paltry 2.2-pound difference between the low-fat and high-fat diets after one year is the total average weight loss in the studies designed for weight loss – a mere 8.25 lbs. after 1 year. Instead of declaring low carbohydrate, higher fat diets a clear winner over low fat, higher carbohydrate diets (especially considering the 2.2 pound difference), we should be asking why it’s tough to stay on a diet, any diet? Why aren’t study participants losing more weight? I don’t have the answer to these questions and leading weight loss researchers don’t seem to have a complete picture right now either.

If you want to lose weight, choose a lower calorie diet primarily based on high quality foods or create your own plan that fits into your lifestyle and is one you can stick with it. There are many diets that could, potentially, work for you. If you want to try a low carbohydrate diet for a while, by all means go for it (especially if you need to see that number on the scale move pretty quickly)! If cutting carbs sounds like being in detention, then skip that approach! I’m giving you permission to alter your plan as often as you need to based on changes in your lifestyle (some research papers actually suggest doing this and I am a huge fan of this approach), motivation, and results.

Conceptually, low carbohydrate diets are very easy. You don’t have to worry about portion sizes, log calories, count points or determine if you have to eat less at dinner to make up for a lunchtime splurge. Decision-making is boiled down to: it contains carbs and therefore off my diet or it is low in carbs and the carbs it does contain are high in fiber so I can eat it. Just don’t buy into the hype that low fat, higher carbohydrate diets are the only way to lose weight or that these diets are better, over the long term, than other dietary approaches that also cut calories.

References

Tobias DK, Chen M, Manson JE, Ludwig DS, Willett W, Hu FB. Effect of low-fat diet interventions versus other diet interventions on long-term weight change in adults: a systematic review and meta-analysis. Lancet Epub before print. 29 October 2015.

Greenberg I, Stampfer MJ, Schwarzfuchs D, Shai I; DIRECT Group. Adherence and success in long-term weight loss diets: the dietary intervention randomized controlled trial (DIRECT). J Am Coll Nutr 2009;28(2):159-68.

Franz MJ, VanWormer JJ, Crain AL, Boucher JL, Histon T, Caplan W, Bowman JD, Pronk NP. Weight-loss outcomes: a systematic review and meta-analysis of weight-loss clinical trials with a minimum 1-year follow-up. J Am Diet Assoc 2007;107(10):1755-67.

Hall KD. Predicting metabolic adaptation, body weight change, and energy intake in humans. Am J Physiol Endocrinol Metab 2010;298(3):E449-66.

Hall KD, Sacks G, Chandramohan D, Chow CC, Wang YC, Gortmaker SL, Swinburn BA. Quantification of the effect of energy imbalance on bodyweight. Lancet 2011; 378(9793).

Rosqvist F, Iggman D, Kullberg J, Cedernaes J, Johansson HE, Larsson A, Johansson L6, Ahlström H, Arner P, Dahlman I, Risérus U. Overfeeding polyunsaturated and saturated fat causes distinct effects on liver and visceral fat accumulation in humans. Diabetes 2014;63(7):2356-68.

 

 

 

Can You Lose Fat and Gain Muscle at the Same Time?

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Eat fewer calories than you burn each day and you’ll lose weight. There’s one major issue with this time-tested approach: you’ll probably strip away more than just body fat. Weight loss, especially fast weight loss, achieved after crash dieting or drastically slashing calorie intake, leads to a decrease in muscle mass and subsequent drop in metabolism. A slower metabolism means your body needs even fewer calories to maintain your new weight (weight loss alone = fewer calories needed to carry around a smaller body, add muscle loss and your calorie needs drop even more). In addition, with less muscle you won’t be able to push yourself as hard during workouts (and therefore burn as many calories). This can put you on the fast track to yo-yo dieting, weight loss and regain. There’s a much better approach and a recently published study highlights how you can lose body fat and gain muscle at the same time.

crash dieting leads to muscle loss

In this article I’ll cover:

  1. How dieting can slow your metabolism;
  2. The latest evidence on losing fat and building muscle at the same time;
  3. Why researchers didn’t use a low carbohydrate diet;
  4. How you can keep the weight off.

How Dieting Slows Your Metabolism

When you eat fewer calories than you need each day, your body is forced to pull from its backup supply, body fat and muscle, to maintain your energy (calorie) needs. Some people lose a substantial amount of muscle when dieting, 30% or more, of their initial muscle mass. In addition to a decrease in muscle mass and slower metabolism, lower calorie diets decrease the intracellular signaling necessary for the synthesis of new proteins in muscle. Plus, muscle tissue may be less sensitive to protein when you’re dieting. In other words, it’s really tough to build muscle when dieting to lose weight. Based on these physiological changes, there’s an age-old theory suggesting it’s impossible to gain muscle and lose fat at the same time. However, scientists from McMaster University in Canada found it is not only possible but also, doable even when losing a substantial amount of body fat in a relatively short period of time.

Building Muscle While Losing Body Fat

In the McMaster University study, young overweight recreationally active men (prior to the study they exercised 1-2 times per week) were placed on an intense four-week diet and exercise program. Their diet contained 40% fewer calories each day than needed for weight maintenance. All meals were prepared and provided to participants during the study. The men were randomly selected for one of two diet groups:

  Higher Protein Group

 

Lower Protein (Control Group)

 

Total daily calorie intake 15 calories per pound of lean body mass 15 calories per pound of lean body mass
Macronutrients 35% protein, 50% carbohydrate and 15% fat 15% protein, 50% carbohydrates, 35% fat
Total daily protein intake 1.09 grams of protein per lb. body weight (2.4 grams of protein per kg) 0.55 grams of protein per lb. bodyweight (1.2 grams of protein per kg) – 2x the RDA (0.8 g/kg) for protein

 

Per meal protein intake 0.22 grams of protein per lb. of body weight

 

0.10 grams of protein per lb. of body weight

 

Dairy shakes 3- 4 / day including one after exercise (depending on body weight; higher protein, lower carbohydrate shakes compared to the Lower Protein Group)

 

3- 4 / day including one after exercise (depending on body weight; lower protein, higher carbohydrate shakes compared to the Higher Protein Group)

 

Training Program
Supervised workouts consisted of full-body resistance circuit training twice per week and high intensity interval training six days per week. In addition to their structured exercise program, all participants were instructed to get at least 10,000 steps per day as monitored by a pedometer worn on their hip.

Resistance Training Circuit
2 times per week
3 sets of 10 reps at 80% 1 RM with the last set of each exercise to failure
No rest between sets
1-minute rest between each circuit

Sprint Interval Training
1 time per week
Four to eight 30-second bouts on a stationary bike (participants started with four sets and progressed to eight sets)
4 minutes rest between bouts

Modified High Intensity Interval Training
1 time per week
10 bouts of all-out sprint for one minute at 90% VO2max
1-minute rest intervals at 50% VO2max

Time Trial
1 time per week as fast as possible until approximately 250 calories were burned

Plyometric bodyweight circuit
30-second rest between exercises

Results
Both the lower protein and higher protein groups lost weight with no significant difference between groups. Men in the higher protein group gained 2.64 lbs. of muscle and lost 10.56 lbs. of body fat while men in the control group gained little muscle (0.22 lbs.) and lost 7.7 lbs. of fat. Both groups improved all but one measure of strength in addition to aerobic and anaerobic capacity. There were no differences between groups in strength, power, aerobic fitness or performance at the end of the study.

In this study, a higher protein, reduced calorie diet combined with a high intensity circuit-training program including interval training and sprints helped participants build muscle. In addition to their total protein intake, participants in the higher protein group also consumed more protein per meal (approximately 49 grams per meal) than those in the lower protein group (approximately 22 grams per meal).

Why Didn’t They Cut Carbohydrates?

Low carbohydrate diets are not only popular, but they may lead to greater weight loss (in overweight and obese individuals), initially, than higher carbohydrate, low fat diets (some of this is water weight). However, when giving up carbohydrates you also sacrifice something else, intense training. Carbohydrates are the primary source of fuel used during high-intensity exercise because your body can readily access and utilize them for energy. Fat is a slow source of energy and therefore, your body cannot access and use fat quickly enough to sustain high intensity training. In this study, both groups of participants consumed 50% of their calorie intake from carbohydrate. If the study authors cut carbohydrates, the participants wouldn’t make it through their high intensity training program that was specifically designed to take off fat and increase muscle mass.

Keeping the Weight Off

Consider a program like the one used in this study a short-term jumpstart. It isn’t sustainable over a long period of time. The transition to a longer-term approach after weight loss should include a gradual increase in calorie intake while maintaining a higher protein diet (at least 0.55 grams of protein per lb. of body weight to maintain muscle while considerably more, along the lines of 1.09 – 1.41 grams of protein per lb. of body weight may be necessary to continue building muscle during periods of reduced calorie intake). This gradual increase in calorie intake is important because substantial weight loss results in a slower metabolism even if you maintain or build muscle during your jumpstart weight loss program. It isn’t entirely clear why this happens and the drop is greater than scientists can predict based on a decrease in muscle mass. Even if you build some muscle, this won’t rev fire up your metabolism to make up for a drastic decrease in body weight.

One pound of muscle burns a measly 5.9 calories per day at rest while a pound of fat burns 2 calories per day at rest.

Greater weight lost while dieting means an even greater drop in metabolism – something dieters must account for so they can maintain their new weight.

In addition to slowly increasing calorie intake and consuming a higher protein diet, each meal should contain at least 25 – 30 grams of protein. We don’t know the exact amount of protein per meal needed to maximally stimulate muscle building.

Your exercise regimen should continue to include resistance training and you’d be wise to continually vary your training program. Be sure to move each day as well. Research shows many people naturally adjust to greater amounts of aerobic exercise by decreasing their activities of daily living. They exercise intensely at the gym and then sit the rest of the day. Circumvent this by using one of the many devices that counts steps each day. Also, consider doing more work around your house including cleaning, mowing your lawn, gardening, and washing your car. Get moving and stay moving all day long.

If you want to get rid of your love handles while building a six-pack at the same time, combine an effective resistance training and high intensity interval-training program with a reduced calorie, higher protein diet. Your diet and exercise program does not need to be as rigorous as the one in this study. Instead, you can adjust the McMaster University approach to fit your lifestyle, though your results may take more time. Once you reach your goal weight, slowly transition your training program and diet to an approach you can live with.

References
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Johannsen DL, Knuth ND, Huizenga R, Rood JC, Ravussin E, Hall KD. Metabolic Slowing with Massive Weight Loss despite Preservation of Fat-Free Mass. J Clin Endocrinol Metab 2012; 97(7): 2489–2496.

Ravussin E, Bogardus C. Review Relationship of genetics, age, and physical fitness to daily energy expenditure and fuel utilization. Am J Clin Nutr 1989; 49(5 Suppl):968-75.

Phillips SM. A Brief Review of Higher Dietary Protein Diets in Weight Loss: A Focus on Athletes. Sports Med 2014; 44(Suppl 2): 149–153.

Longland T, Oikawa SY, Mitchell CJ, Devries MC, Phillips S. Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial. Am J Clin Nutr 2016;103:738-46.

Heydari M, Freund J, Boutcher SH. The effect of high-intensity intermittent exercise on body composition of overweight young males. J Obes 2012;2012:480467.

Areta JL, Burke LM, Camera DM, West DW, Crawshay S, Moore DR,Stellingwerff T, Phillips SM, Hawley JA, Coffey VG. Reduced resting skeletal muscle protein synthesis is rescued by resistance exercise and protein ingestion following short-term energy deficit. Am J Physiol Endocrinol Metab 2014;306:E989–97.

Pasiakos SM, Vislocky LM, Carbone JW, Altieri N, Konopelski K, Freake HC, Anderson JM, Ferrando AA, Wolfe RR, Rodriguez NR. Acute energy deprivation affects skeletal muscle protein synthesis and associated intracellular signaling proteins in physically active adults. J Nutr 2010;140:745–51.

Hector AJ, Marcotte GR, Churchward-Venne TA, Murphy CH, Breen, von AM, Baker SK, Phillips SM. Whey protein supplementation preserves postprandial myofibrillar protein synthesis during short-term energy restriction in overweight and obese adults. J Nutr 2015;145:246–52.

Murphy CH, Churchward-Venne TA, Mitchell CJ, Kolar NM, KassisA, Karagounis LG, Burke LM, Hawley JA, Phillips SM. Hypoenergetic diet-induced reductions in myofibrillar protein synthesis are restored with resistance training and balanced daily protein ingestion in older men. Am J Physiol Endocrinol Metab 2015;308:E734–43.

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