Tag: Lifestyle Intervention

Why the Scale Isn’t the Best Measure of Weight Loss

On By Dr. Scott RennieIn Weight Loss & Metabolic HealthLeave a comment

When patients bring up weight loss, the number on the scale is almost always the first thing out of their mouth. The scale is a poor narrator. What is being lost, fat or muscle or some mix of the two, matters as much as how much of it is gone. That distinction is body composition, and it drives health, function, and what happens years down the line.

Research from Dr. Dympna Gallagher and colleagues has mapped how body composition shifts during weight loss, and how activity, resistance training in particular, protects muscle through it.

Not all weight loss is the same. Weight comes off as a mix of fat and fat-free mass, the latter including muscle, water, and bone. Work from the 1980s estimated that 20 to 30 percent of the weight lost on a standard diet comes from lean mass (Webster et al., 1984). That fraction is not fixed. Age, diet quality, activity, and the speed of loss all move it. Steady loss of about half a kilogram a week protects muscle better than anything faster (Council on Scientific Affairs, JAMA 1988). This matters because Framingham data link muscle loss to higher mortality while fat loss lowers risk (Allison et al., 1999).

Exercise changes the arithmetic. Gallagher’s review and work from Beavers and colleagues found that structured exercise cuts muscle loss during weight reduction nearly in half. In one trial in older adults, resistance training brought lean mass loss down from 16 percent to 10 percent (Beavers et al., 2017). Resistance work beat aerobic exercise at preserving muscle even when both groups lost similar total weight, and combining them produced the best result: more fat lost, better strength, better mobility (Davidson et al., 2009).

Body composition also drifts with age even when the scale holds steady. The Health ABC study found people gradually losing skeletal muscle and subcutaneous fat while gaining visceral fat and fat within muscle tissue (Newman et al., 2005). Less muscle with more central fat raises metabolic risk and costs mobility, and it is a large part of why sarcopenic obesity shows up in older adults.

Bariatric surgery offers a natural experiment in what happens under very large weight loss. Gallagher’s group found that surgical patients lost substantial fat while holding onto muscle long term, provided nutrition stayed adequate and they resumed activity afterward (Davidson et al., 2018). Skeletal muscle remained relatively stable at five years despite major reductions in fat mass.

What I tell patients comes down to this. Do not manage your health by the scale alone. Protect the muscle. Resistance training two or three times a week, adequate protein while calories are restricted, and goals you can actually sustain. A 5 to 10 percent reduction over roughly 20 weeks improves metabolic risk and is realistic for most people (Wadden et al., 1996). I would rather track grip strength or how many chair stands someone can do than watch the scale week to week, because those numbers tell me whether the weight coming off is the weight we wanted to lose.

That is the whole point of paying attention to composition. Losing fat while holding muscle buys better health, more independence, and better metabolic outcomes. Resistance training is not an optional extra here. It belongs in the treatment plan alongside everything else.

Scott Rennie, D.O.

References

Gallagher D. Body Composition Changes with Weight Loss, Including Physical Activity Regimens. Columbia University, 2022.

Wadden TA et al. Am J Clin Nutr. 1996;63(3 Suppl):294S-298S.

Council on Scientific Affairs. JAMA. 1988;260(17):2547-2551.

Webster JD et al. Can J Appl Sport Sci. 1984;9(3):111-118.

Allison DB et al. Int J Obes Relat Metab Disord. 1999;23(1):1-7.

Beavers KM et al. Obesity. 2017;25(9):1476-1483.

Davidson LE et al. Arch Intern Med. 2009;169(2):122-131.

Davidson LE et al. Obesity. 2018;26(3):500-506.

Newman AB et al. Am J Clin Nutr. 2005;82(4):872-878.

Board Certified in Obesity Medicine and Family Medicine

This blog is for educational purposes only and does not constitute individual medical advice. Always consult your own physician before making changes to your health, medications, or treatment plan.

Is Yo-Yo Dieting Bad for You? Weight Cycling Explained

On By Dr. Scott RennieIn Weight Loss & Metabolic HealthLeave a comment

A lot of my patients describe the same arc. They work hard, lose weight, feel good for a while, and then months or years later it comes back. That repeated loss and regain is weight cycling. It is common, and it is hard on people both physically and emotionally.

The question I hear most often is whether it is even worth trying if the weight is coming back anyway. The research answers that more clearly than it used to, and the answer is yes.

Weight cycling generally means repeated intentional loss followed by unintentional regain. Some researchers set the bar at a 10 percent change in body weight occurring three or more times. Depending on the study, it affects 20 to 35 percent of men and up to half of women (Montani et al., 2015).

Why does the weight return? Biology pushes back harder than most people anticipate. After weight loss, resting energy expenditure falls further than body size alone would predict, and this metabolic adaptation can persist for years, meaning the body burns less than expected (Fothergill et al., 2016). Hormones move too. Leptin drops, hunger hormones climb, and patients end up hungrier and less satisfied by meals than they were before (Sumithran et al., 2011). The body also tends to compensate for exercise by raising appetite. Together these explain why maintenance is the hard part, not the losing (Thomas et al., 2012).

The real question is whether the cycling itself does damage. Large reviews and cohort studies have not found strong evidence that weight cycling raises mortality or major chronic disease risk when the weight loss is intentional and supervised (Mehta et al., 2014). Some work suggests regain may favor fat over muscle, visceral fat especially, though the findings are inconsistent (Mackie et al., 2017).

The psychological picture is better than most people assume. Foster and colleagues found that patients who regained weight still reported improvements in mood, hunger, and eating behavior after the loss phase (Foster et al., 1996). Other work has found no consistent long-term harm from the pattern itself (Osborn et al., 2011).

So should patients keep trying? The National Task Force on the Prevention and Treatment of Obesity concluded in 1994 that weight cycling should not deter people from attempting weight loss, and that position has held up (National Task Force, JAMA 1994). The benefits of intentional loss, lower blood pressure, better lipids, better glucose control, better quality of life, generally outweigh the risk of regaining.

One of my patients lost about 8 percent of her body weight through diet and walking. A year later most of it had come back. During the stretch she kept it off, though, her blood pressure normalized and she came off one of her antihypertensives. The weight returned. The benefit she got during that window was real and measurable, and the research says her experience is the rule rather than the exception.

What I steer patients toward is sustainable habit rather than another aggressive diet. Regular activity, consistent eating patterns, decent sleep, and watching the trend line instead of the daily number. A setback does not undo the progress. Staying connected to support, whether that is a clinician, a dietitian, or counseling, matters more than most people expect.

Weight cycling is real and it is discouraging. It is not a reason to stop. Even temporary weight loss buys real health, and the useful reframe is to treat weight management as ongoing care rather than a project with an end date.

Scott Rennie, D.O.

References

Montani JP et al. Obesity Reviews. 2015.

Fothergill E et al. Obesity. 2016.

Sumithran P et al. NEJM. 2011.

Thomas DM et al. Obesity. 2012.

Mehta T et al. Obesity Reviews. 2014.

Mackie GM et al. Obes Res Clin Pract. 2017.

Foster GD et al. J Consult Clin Psychol. 1996.

Osborn CY et al. Ethn Dis. 2011.

National Task Force on the Prevention and Treatment of Obesity. Weight cycling. JAMA. 1994;272(15):1196-1202.

Board Certified in Obesity Medicine and Family Medicine

This blog is for educational purposes only and does not constitute individual medical advice. Always consult your own physician before making changes to your health, medications, or treatment plan.