Fast Weight Loss & Hunger Hormones

Posted: January 27, 2012 | Author: Helen Kollias | Filed under: Blog, Research Reviews | Comments Off

Summary: Short-term very-low-calorie dieting disrupts powerful hormones that control appetite, hunger, and satiety for up to a year after a strict diet. Crash diet now, feel hungry later… even several months later.

What is the top New Year’s resolution? Lose weight.

Every year, people with good intentions set out to lose weight, only to have even more weight to lose the next year later. (Resolutions seem like such a good idea when you’ve got a party horn in your hand and a gold cardboard top hat on your head, swimming in a champagne-induced fog.)

One problem is that people try to lose weight quickly. Unfortunately, even if they manage to drop a few pounds fast, they bounce right back… and often, keep on gaining.

By slowing down the weight loss process and teaching life-long healthy habits, PN’s very own Lean Eating program is designed to avoid the cycle of perpetual weight loss.

Now, research confirms our methods. (But we knew that already.) Only slow and steady progress leads to lasting change. Why?

Appetite hormones: Why self control is not the problem

Myth: weight loss is all about self control.

People berate themselves or are judged by others for carrying a few extra pounds. To be fat means you’re weak-willed, spineless, and/or impulsive.

Fact: Powerful hormones control our perception of appetite and hunger, as well as our eating behaviour.

While you still have the option of self-control, your body definitely has a strong voice in the matter. And “willpower” breaks down easily under stress; when blood sugar is low; and/or in environments that don’t support weight loss (like an office where everyone has a candy dish and it seems like someone has a birthday cake every day).

Here are some of the more well-known hormones that influence appetite, hunger, and satiety.

Cholecystokinin (CCK)	Released in the small intestine when fats and proteins are eaten. Receptors that respond to CCK are not only found in the gut but also in the brain. In the brain CCK depresses hunger, meaning the more CCK you have floating around the less hungry you are, and the less you’re likely to eat. This is why a lower-carb, higher-protein, higher-fat diet tends to make people feel fuller longer.
Glucagon-like peptide-1 (GLP-1)	Delays stomach emptying time that may make you feel more full.
Gastric inhibitory polypeptide YY (PYY)	Secreted by small bowel and colon in response to food. Inhibits hunger.
Leptin	Mostly released by fat; decreases hunger. If you want to lose weight you’d want to have more leptin.
Ghrelin	Made mostly in the stomach; acts on the brain (hypothalamus) to stimulate hunger. If you want to lose weight, you want less ghrelin.

For more about leptin and ghrelin take a look at another research review of mine on leptin and ghrelin.

The ideal hormone combo to suppress appetite and help you lose weight would be:

• more CCK, GLP-1, PYY, and leptin
• less ghrelin

What happens to hormones over the long haul?

The study I’m reviewing this week looks at what happens to appetite hormones after 10 weeks of dieting up to 1 year later. Yup, your lemon-cayenne diet from last year may be making you feel more hungry this year.

Sumithran P, Prendergast LA, Delbridge E, Purcell K, Shulkes A, Kriketos A, Proietto J. Long-term persistence of hormonal adaptations to weight loss. N Engl J Med. 2011 Oct 27;365(17):1597-604.

Methods

This year-long study involved 50 people with BMI between 27 and 40 (classified as overweight and obese), who went on a crazy low-calorie diet for 10 weeks (though the researchers called it a very-low energy diet).

What’s a crazy low calorie diet? Oh, say 500-550 kcal for people that had an average weight of 95 kg (209 lb), which is one-third of their basal metabolic rate. To live without moving at all, these volunteers would need about 1700 kcal on average. No question they were really hungry and needed a hell of a lot of will power to stay on this diet.

The problem with calorie math

Basal metabolic rate BMR is the amount of energy you need to live when at rest. The most common equation to calculate BMR is the Harris-Benedict equation. BMR calculation for men BMR = 66.5 + (13.75 x weight in kg) + (5.003 x height in cm) – (6.755 x age in years) BMR calculation for women BMR = 655.1 + (9.563 x weight in kg) + (1.850 x height in cm) – (4.676 x age in years) Here’s an online BMR calculator, if you don’t want to do the math.

This intake of 500-550 kcal means that each day these volunteers are eating at least 1200 kcal less than they need.

Since fat has 3600 kcal/pound, you could use basic (and flawed) calorie counting to figure they should lose a pound (0.45 kg) of fat every three days. At the end of 10 weeks (70 days) they should lose just over 23 pounds (10.6 kg), or 11% body weight in fat.

The problem with thinking of yourself as just fat that’s burned like a candle is that you overlook things like hormones that through evolution respond to starvation by storing calories more efficiently.

A few hundred years ago, it was a good thing that your body responded to starvation by storing as much fat as possible. Thrifty hormones saved lives. Now when starvation is self-induced in a sea of food it causes problems.

Results

During the first 10 weeks of the study, when the volunteers were eating a very low calorie diet, they lost 9.4 kg (20.7 lb) of fat and 4.1 kg (9 lb) of lean body mass, but that didn’t last over the next year.

As the year went on after the diet, they slowly gained half the weight they lost. At first glance, that doesn’t sound too bad. They lost a fair bit of weight in a short period, and then a year later, they were still ahead of the game.

Hormonal effects: short term

The problem is what happens to these volunteers’ hormones — the hormones like leptin, ghrelin, peptide YY, etc. — that regulate appetite, hunger, and satiety.

After 10 weeks of starvation the volunteers had less leptin, peptide YY, and cholecystrokinin, as well as more ghrelin and gastric inhibitory polypeptide. The result: The volunteers felt more hungry. Cue the need for even more will power to keep the weight off. Sound familiar?

Hormonal effects: long term

We knew that crash dieting messes up appetite regulatory hormones for a short period, but until now, nobody had looked at the long-term effects of very low calories on these hormones.

Why didn’t anyone look at what happened a year or more later?

Well, it’s hard to get people signed up for a year-long anything, let alone having them go on a starvation diet for over two months first. Plus, it’s a bit of a surprise that a short term diet would do much a year later. These scientists must have had to convince a lot of people that this study was worth doing.

One year after dieting the volunteers still had less leptin, peptide YY, and cholecystokinin; and more ghrelin, gastric inhibitory polypeptide and pancreatic polypeptide.

What happened to hunger? Still higher after a year. Think about that. A full year after dieting, the volunteers still felt more hungry. No surprise that most dieters regain weight lost and more… eventually.

Conclusion

If you try to lose weight quickly, you’ll end up trying to lose it every year instead of taking a year to lose the weight once.

It’s clear that very low calorie dieting has long term impact on hunger and appetite hormones lasting at least a year. Now imagine what multiple crash diets might do.

By the way, stringent and chronic restriction also affects hormones that control gastric motility (the speed at which food is processed) and neurotransmitters (brain chemicals).

Thus, if you regularly “diet”, not only do you end up always hungry, you have indigestion and “brain hamsters” like anxiety or depression, and you rarely feel psychologically satisfied by eating — you always want more, or have strong cravings. Show me a “professional dieter” and I’ll show you someone who feels generally lousy physically, mentally, and emotionally. Hormonal disruption is strong stuff.

Could yo-yo dieting lead to cumulative changes in appetite regulation hormones? Very likely. Several years of yo-yo dieting later, you may feel much more hungry than when you started. Good luck with willpower then.

Bottom line

Lose weight quickly while nearly starving, only to gain most of it back (or more) and feel hungrier than when you started. Or lose weight slowly, for good, and feel better than ever… eventually.

What would you choose? If you want door #2… well… have we got a program for you.

Click here to join the waiting list.

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Improve Body Image, Improve Your Body

Posted: January 20, 2012 | Author: Helen Kollias | Filed under: Blog, Research Reviews | Comments Off

Summary: Paradoxical as it sounds, new research shows that a better body image could actually help you lose more body weight.  In other words, accepting your body as it is and spending less time thinking about it is the best way to live a leaner, healthier lifestyle.

We’re bombarded with images of unattainable, unrealistic, and unhealthy beauty. Start with an average model, who has a BMI of 16.5. Add lots of computer software and hours of editing. You end up with a distorted, imaginary, arguably non-human view of what purports to be a “normal” and beautiful body.

For some perspective, at my height of 5’8″ (173 cm), I would have to weigh 107.5 lb to have a BMI of 16.5. Since my normal weight is about 140 lb, I would have to lose all my body fat plus nearly 10 pounds of lean body tissue.

Then of course, I’d be airbrushed into oblivion. (To get an idea what is possible with digital enhancement, take a look at a weight loss session done with Adobe Photoshop software).

But here’s the paradox. Bizarrely, impossibly thin images are all around us. Yet more people are overweight and obese than ever before. Seems odd. You’d think that having more pressure would push people into the direction of losing weight, but the opposite is happening instead. Why?

Being a biologist I like to think that biology matters and can explain things more than, say, squishy things like feelings and perceptions. So I might have argued that weight loss was simply energy in (food) versus energy out (movement).

Looks like us geeks might have been a little simplistic.

In this week’s research review, we see that for people struggling with their weight, how they see their body is just as important as — if not more important than — the biology of their body.

Body image: evaluation and investment

We all went through an awkward stage as a teenagers. Heck, you may still be in an awkward stage 30 years later.

Looking in the mirror or fretting over a picture. Is that what I really look like?! The horror! If I could just lose/gain x pounds, lift this, and tuck that, THEN I would be happy. You know the drill.

Body image is how we perceive our physical appearance — good or bad — as well as how important your body perceptions are to you.  Body image is separated into two parts (aka attitudinal dimensions):

1. Evaluative body image: How you think and feel you look, as well as how happy you are with your body. This is your cognitive appraisal and associated emotions (aka what you think or feel). It doesn’t necessarily mean this is reality.

2. Body image investment: How important body image is to you and how much body image affects your daily life. Being preoccupied with the way your body looks (body concern) is a hallmark of dysfunctional body image investment. Another part of body image investment is social physique anxiety, which makes you anxious in social settings and during interactions with others because you feel that others are judging your body.

So, you might not like your body much (evaluation) but not really care an awful lot (investment). This might mean you treat your body like an ugly but necessary inconvenience, like having to clean out the cat’s litter box. Gross, but what are ya gonna do, you think.

Or, you might think you look great (evaluation) and find that greatness really, really important as well (investment), which might mean that you spend a lot of time being afraid of losing that hot bod.

Of course, many of us have the worst of both worlds. We don’t like our bodies, and because we’re so invested in body image, our perceived-grotesque physiques make us want to hide under a rock.

Whether evaluation and/or investment, we tend to think of “body image” as something that happens inside our head. But could it affect our actual bodies?

What role does body image play in weight loss?

In this week’s review, I look at whether improving body image may help women lose weight over a year-long behaviour change program.

Carraça EV, Silva MN, Markland D, Vieira PN, Minderico CS, Sardinha LB, Teixeira PJ. Body image change and improved eating self-regulation in a weight management intervention in women. Int J Behav Nutr Phys Act. 2011 Jul 18;8:75.

Methods

A group of obese women went through a year-long weight loss program that focused on behaviour changes.

You may be thinking, Well aren’t all weight loss programs behaviour changes? Yes, but this one focused on self-regulation of eating (with an approach known as self-determination theory) rather than calorie counting or specific meal plans.

Our own Lean Eating program at PN focuses on eating self-regulation, which bothers some people who may be expecting a auto-pilot type of approach. What — I don’t get a list of meals? Or a meal plan to follow? You mean I have to pay attention to how my body feels and I have to make decisions!?

Now, I get that it’s often easier to let other people make decisions for you. However, the advantage of self-regulated eating is that mindful, voluntary and self-directed eating is more sustainable long-term, while fostering independence. You learn the skills you need to eat better… for life… without someone else looking over your shoulder.

Scary at first, but a lot more sustainable and useful. (Trust us. We’ve helped thousands of clients.)

Self-regulation

Several factors guide self-regulation of eating:

• confidence that you can do it (eating self-efficacy);
• consciously controlled eating that isn’t too rigid (highly flexible cognitive restraint );
• less emotional eating; less eating triggered by specific situations; and less eating because of habits (reduced disinhibition including emotional, situational and habitual cues); and
• less perceived hunger.

The women also increased their level of physical activity, but as with the eating, there were no specific prescriptions for what to do each day.

Body image sessions

Half the women also went to body image enhancement sessions to improve their body acceptance and satisfaction (evaluative body image) and decrease their over-preoccupation with appearance (investment in body image).

Exercises to improve body acceptance and evaluation included:

• looking at a mirror and systematically looking at body parts;
• making realistic goals and expectations for their bodies; and
• creating a realistic ideal body based on their parents’ weight history and their body type.

Exercises to improve investment in appearance included:

• understanding body image;
• finding the cause of the disorder (what situations — social and personal — triggered dysfunction?);
• keeping a diary to record negative self-talk and the feelings it causes;
• helping the women to cope with prejudice;
• helping the women let go of the belief they need to look different in order to be happy.

How do you measure body image?

You might be wondering how you measure body image and the different parts that make it up. There are a series of questionnaires and scales to indicate someone’s body image.

For evaluative body image, one of the more interesting and easy scales to use and understand is the figure rating scale (Figure 1). This provides a series of body outlines numbered 1 (very thin) to 9 (very heavy).

Participants pick the number they think fits their actual body size, and then they pick the number that represents their ideal body size. The bigger the difference (self-ideal discrepancy) the more body image issues a participant has.

Keep in mind this is perceived body size, not real body size. People may actually be their ideal body size but not think so. If you think you’re a 9 on the scale but you’re really a 1, you’ve definitely got a problem.

Body image investment is assessed using questionnaires that ask things like:

• How often do you feel fat when taking a bath?
• How often has your body shape/size kept you from concentrating?
• How nervous do you feel about your body in social settings?

 

Results

Improved body image

The body image sessions worked. The women in these sessions improved both evaluative body image and body image investment.

Improved eating self-regulation & weight loss

Improving body image also improved eating self-regulation. With better eating, there was better weight loss.

The body image group lost 7.3% of their body weight, while the control group lost only 1.7% of their body weight.

It makes sense that better eating means more weight loss, but seems odd that a better body image would help weight loss. Wouldn’t you think that people should lose weight first… and then feel better about their bodies?

Not in this case. The group that got care, counselling, and compassion kicked ass. Goes against the drill sergeant/tough love approach, doesn’t it?

Using a mathematical model (partial least squares) the researchers found that changes in body image investment was a little more important for weight loss than body image evaluation. In other words, to lose weight, it’s more important to let go of rigid investment in body size and shape than it is to always feel great about yourself.

(After all, remember our hypothetical people who feel good about their body, but are afraid of losing it? They’re much more likely to rigidly control their eating and exercise, which sets them up for problems like diet rebounds, exercise compulsions, and binge eating later on. Plus, if you’re not as invested in your body image, you realize that small things like day-to-day weight fluctuations aren’t that big a deal.)

Conclusion

You’d think people would be motivated to change if they were unhappy with their body. In fact, the opposite is true: Greater body image dissatisfaction actually hinders weight loss.

You may need a certain amount of dissatisfaction with your current body if you want to change it, but more isn’t better. Pointing out that someone is overweight or obese, or beating up on yourself, doesn’t make you more motivated. Nor does it help you get leaner.

We know this to be true. In Lean Eating, we use an “awesomeness-based coaching” approach. We don’t spend time pointing out your “flaws” or “problem areas” (imaginary or otherwise). We find what’s already awesome about you, right now, no matter what your body looks like… and help you do and feel more of that.

(And just a warning: We have a Five-Pushup Rule in Lean Eating: Self-criticism gets you five pushups. We know that negative self-talk doesn’t do you any good. So we pushup that nasty stuff right outta you.)

This study shows that improving body image helps with weight loss. And it seems that spending less time worrying about how your body looks and how other people may scrutinize your body is a bigger part of the puzzle than how unhappy you are about your body.

Want to lose weight?

• Stop obsessing about your body. If possible, try to get “outside yourself” — into a bigger world full of activities, experiences, social causes, and other things more interesting than whether you can see your abs.
• Pursue self-acceptance, self-care and self-compassion… not self-criticism.
• Pay more attention to what you eat — eat slowly and mindfully.
• Move your body more.

Simple, but not necessarily easy.

Bottom line

Whether you’re coaching a client or are interesting in losing weight yourself, improving body image can help you lose weight.

As counter-intuitive as it sounds, accepting your body as it is and spending less time thinking about your body can improve your weight loss. You still have to eat a little less and move around a little more… but at the very least, you’ll also like yourself at the end of the day.

References

Bhuiyan AR, Gustat J, Srinivasan SR, Berenson GS. Differences in body shape representations among young adults from a biracial (Black-White), semirural community: the Bogalusa Heart Study. Am J Epidemiol. 2003 Oct 15;158(8):792-7.

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