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By: Hassan S Dashti, PhD

The most popular New Years resolution by far is weight loss. People kick-start their new year on new ‘detox’ or fad diets with hopes to lose some weight or, less commonly, to adopt a healthy lifestyle, only to quit a few months later. Traffic to websites like caloriecounter.com and weightwaterchers.com hits an all time high in January! (1) People often envision January 1 of every year as an empowering and motivating moment that enables them to consider making these daring lifestyle changes. People might be less inclined to make these commitments on arbitrary dates like March 1 or October 19. With emerging evidence suggesting seasonal changes in the environment and human physiology, driven primarily by seasonal changes in sunlight and temperature, is it possible that certain start dates or seasons are more conducive to successful weight loss?

Seasonal variations have been observed for numerous communicable and non-communicable diseases (2) and both biological and behavioral traits. One of the earliest observations of seasonal variation in a disease was that of rickets, a disease resulting from vitamin D deficiency (3). Clinical observations indicated that rickets was common in spring, but rare in fall. The subsequent finding of seasonal variation in plasma 25(OH)D levels suggested that summer sunlight exposure was indeed an important determinant of vitamin D status. For more complex traits, like obesity, the seasonal etiology, if present, is likely to be multifactorial!

Successful weight loss is largely determined by the ability to reduce overall caloric intake, which depends on food availability and internal hunger cues. Living at a time where food is essentially abundant year-round in the Western world, people are typically not dealing with food shortages. For most processed foods, seasonal price variability is also absent, particularly in metropolitan areas, so people’s intakes are likely to be homogenous year-round (4,5). However, seasonal price variability of nutrient dense fruits and vegetables may limit a person’s likelihood to adhere to diets higher in fruits and vegetables. For example, strawberry prices tend to decrease through the first four months of the year and rise again from September to December. Fresh apples, on the other hand, have a fairly weak seasonal price pattern as a result of new apple varieties with later harvest dates and sophisticated storage technology. But it seems that despite the constant supply of most foods at steady prices, seasonal variation in dietary intake may exist. In the Framingham Heart Study, for example, self-reported total energy intake was 86 kcal/day higher during the fall than in the spring (6). Also, percentage of calories from carbohydrate, fat and saturated fat showed slight seasonal variation, with a peak in the spring for carbohydrate and in the fall for total fat and saturated fat intake. Of course these differences may be due to seasonal differences in self-reporting and recall, but if it’s true, is weight loss in the spring more successful than the fall?

Another important aspect of weight loss to consider is seasonal variability in energy expenditure.

The investigation from the Framingham Heart Study (6) also observed seasonal variation in physical activity, including common activities such as gardening, carpentry, lawn mowing, golf and running for men, and gardening, swimming, health club exercise, dancing and bicycling for women. Not surprisingly, people residing in the Northeast are less inclined to engage in outdoor physical activity. This sedentary lifestyle in the winter may partly explain the reason why people tend to be the heavier in the winter! (7)

Newer studies are investigating more complex physiologic changes that might interfere with energy balance. Recent observations in humans suggest that cold exposure may induce the conversion of white adipose tissue to more metabolically active brown-like adipose tissue (8). This ‘beiging’ effect of cold exposure could potentially have clinical implications for diabetes and obesity. Other studies have observed seasonal variability in metabolism and epigenetics as well (9,10). Whether these physiologic differences can override energy imbalance resulting from seasonal lifestyle differences is currently unknown.

To test whether there are seasonal differences in weight loss success we’d ideally test this in a randomized and controlled weight loss trial whereby people are prescribed hypocaloric diets and assigned random start dates. This can also be investigated analytically in previously conducted weight loss cohorts. Various methodologies are available for the assessment of seasonality and those range from simple comparisons across seasons, to simple models such as fitting monthly counts to a sine curve, or more complex statistical models (2).

Despite the little evidence we have so far relating seasonality and energy balance, healthcare providers, including nutritionists, should account for seasonality in their practice, and tailor their dietary (food and fluids) and physical activity recommendations accordingly – it’d be senseless to recommend berries when they are unavailable at stores or outdoor exercise when it’s uncomfortably warm! But perhaps reaching that point of enthusiasm for weight loss is the most important factor predicting weight loss success, so if January 1 is that date when motivation hits in, then so be it!

References:

2.Christiansen CF, Pedersen L, Sørensen HT, Rothman KJ. Methods to assess seasonal effects in epidemiological studies of infectious diseases–exemplified by application to the occurrence of meningococcal disease. Clin Microbiol Infect. 2012 Oct;18(10):963–9.
3.Stamp TC, Round JM. Seasonal changes in human plasma levels of 25-hydroxyvitamin D. Nature. 1974 Feb 22;247(5442):563–5.
4.Evolving U.S. Fruit Markets and Seasonal Grower Price Patterns, by Kristy Plattner, Agnes Perez, and Suzanne Thornsbury, USDA, Economic Research Service, September 2014
5.Bernstein S, Zambell K, Amar MJ, Arango C, Kelley RC, Miszewski SG, et al. Dietary Intake Patterns Are Consistent Across Seasons in a Cohort of Healthy Adults in a Metropolitan Population. J Acad Nutr Diet. 2016 Jan;116(1):38–45.
6.Ma Y, Olendzki BC, Li W, Hafner AR, Chiriboga D, Hebert JR, et al. Seasonal variation in food intake, physical activity, and body weight in a predominantly overweight population. Eur J Clin Nutr. 2006 Apr;60(4):519–28.
7.Visscher TLS, Seidell JC. Time trends (1993-1997) and seasonal variation in body mass index and waist circumference in the Netherlands. Int J Obes Relat Metab Disord. 2004 Oct;28(10):1309–16.
8.Iyengar P, Scherer PE. Obesity: Slim without the gym – the magic of chilling out. Nat Rev Endocrinol. 2016 Feb 26.
9.van Ooijen AMJ, van Marken Lichtenbelt WD, van Steenhoven AA, Westerterp KR. Seasonal changes in metabolic and temperature responses to cold air in humans. Physiol Behav. 2004 Sep 15;82(2-3):545–53.
10.Aslibekyan S, Dashti HS, Tanaka T, Sha J, Ferrucci L, Zhi D, et al. PRKCZ methylation is associated with sunlight exposure in a North American but not a Mediterranean population. Chronobiol Int. 2014 Jul 30;:1–7.

By Brett Loman

Americans are more aware of what we are eating than ever before, but how we choose to track this information varies quite a lot. Some simply choose to eat more or less of a specific type of food while others record every single thing that they consume. In light of this, I decided to give a few programs a test run. I’ve rated them with 3 stars being the highest.

SuperTracker **½ overall
(free online tool, part of the MyPlate website published by the USDA)
At first impression I was overwhelmed by the multitude of –initially- empty tables and graphs. Once I got into the swing of things, however, my concerns transformed into amusement.
Ease of Use – **
While only be accessed through a web browser, the mobile site is an apt adaptation of the desktop version. Searching for each food is simple enough, but things get cumbersome when selecting the number of units. There is a multitude of units to choose from (e.g. fluid ounces, grams, slices, etc) but the number of those units is limited to a select few choices in a drop down menu.
Foods Available – **
Only some name brands and restaurants are available as choices. However, I could build the majority of complex foods using the basic selections that were available.
Nutrient Information ***
I was surprised by how much detailed information this program offers. Nearly every macronutrient, vitamin, and mineral was addressed in the “Nutrients Report”. This report offers target and average intake side-by-side plus expandable menus that explain which foods contributed (and by what percentage) to that nutrient’s intake.
Recommendation Information – ***
This is where the graphics are exceptionally helpful. They compare my intake to recommendations on the basis of food groups (broken down into things such as refined versus whole grains), empty calories, and individual nutrients.

MyDietAnalysis **overall
(subscription-based website provided by Pearson)
It happens to be the tracker utilized by my university’s introductory nutrition course, so naturally I had to give it a try.
Ease of Use – *
It is only available through a web browser, and the mobile site was not very user-friendly. Commonly chosen foods were under a completely separate menu unhelpfully named “Fast Entry” and only 7 days of intake could be store at one time.
Foods Available – ***
This program has the most specific food items I have seen in a tracker program. Most of the major chain restaurant and grocery brands are represented, cutting out the guesswork involved when building an item from scratch.
Nutrient Information – **
They come awfully close to matching SuperTracker in this respect, but MyDietAnalysis falls short since nearly the same information is presented… on several different pages.
Recommendation Information – **
The “Actual Intakes –vs- Recommended Intakes” report shows you just that for all of the nutrients side-by-side. The bar graph is a nice touch, but the scale for percent of goal met could use a little help, given that I didn’t even realize that it was there at first.

MyFitnessPal *½ overall
(free website and mobile application)
Definitely the app most-mentioned by patients and friends who claim to track their eating habits, tempting me to give it a go.
Ease of Use – ***
By far the greatest strength of this program is its availability as a mobile app. Eating lunch out? Just whip out your phone and track it on the spot. Another handy feature puts the foods you eat most often in a checklist immediately under the search box.
Foods Available – *
What I see as both a major weakness and strength of this app is the ability of any user to create foods, which can then be shared community wide. Sure, it’s great for the company, but the problem lies in the room for inaccuracies and errors.
Nutrient Information – *
Disappointingly, only nutrients routinely found on the nutrition facts panel were available. Again accuracy depends upon who actually entered the food into the database.
Recommendations Information – *
Only 6 of the nutrients could be displayed on my homepage at a time, and the printable report doesn’t even include all nutrients available, nor any averages of my intake compared to recommendations.

Final Thoughts
So are any of these inaccuracies, shortcomings, or lack of information harmful? I’d say probably not. The important thing here is that any of these tools can get people aware of what they are eating so that healthy changes can be made. With that I say happy tracking and please discuss in the comment section below.