Saturday, September 13, 2025

What Are The Biggest Sources Of Sodium In The American Diet?

If you are trying to cut down on the salt in your diet, it is good to know where it might be coming from. Here are the top 10 sources of sodium in the American diet according to the Center for Disease Control.

Bread and rolls

Pizza

Sandwiches

Cold cuts and cured meats

Soups

Burritos and tacos

Savory snacks like chips, popcorn, pretzels and crackers

Chicken

Cheese

Eggs and omelets

Olive Oil And Weight Gain

The Study

Olive oil has been inversely associated with type 2 diabetes, cardiovascular disease and total mortality in the research literature. However, because it is so calorie dense, many limit consumption for fear of weight gain.

In this interesting study, Harvard University looked at olive oil consumption and 4 year weight gain in 121,119 members of the Nurses’ Health Study, Nurses Health Study II and Health Professional Follow-up Study. Subjects were followed for a minimum of 20 years.

The results showed that each ½ tablespoon of olive oil per day was inversely associated with body weight.

American Journal of Clinical Nutrition 2025;121:1149-56

Take Home Message

In this cohort, olive oil consumption did not contribute to weight gain, but surprisingly was associated with weight loss. The researchers believed that the monounsaturated fats in olive oil increased satiety and thermogenesis in these subjects. This would explain the positive impact that olive oil had on their body weight.

You don’t need to limit olive oil if you are trying to manage your weight. It is one of the healthiest fats you can eat, so include it in your diet often.

Obesity And Immune Function

The Study

Obesity has been hypothesized to have a negative impact on immune function. In this interesting study, 24 obese and 31 normal weight subjects were fed a standardized diet for 4 weeks and then had a variety of immune factors tested. The subjects were put on the same diet because what we eat can influence our immune system.

The results showed that measures of immune function such as C-reactive protein, T cell activity and white blood cell counts were significantly worse in the obese subjects.

American Journal of Clinical Nutrition 2025;121:1315-27

Take Home Message

Obesity is thought to be associated with a shift away from immune cell metabolism and toward an increase in glucose metabolism. This can increase inflammation and reduce the efficiency of the immune system. This is just another reason to do your best to keep your weight in the normal range.

Friday, September 12, 2025

Fasting Versus Standard Calorie Restriction

Fasting has become a very popular weight loss strategy. Proponents of fasting believe that it results in increased weight loss and improved health in comparison to standard calorie restriction. Does the research literature back this up? A new study has recently been published that I believe allows us to answer this question definitively.

The Study

This investigation is a systematic review and meta-analysis out of Harvard University and was published in the British Medical Journal (Reference #1). This type of study accumulates all available evidence on a given topic and comes up with a statistical summary estimate. This study included 99 randomized trials that compared different types of fasting to standard calorie restriction:

Here are the results for the 2 most commonly practiced forms of fasting:

Whole day fasting: 24 hour food restriction a few days per week.

Time restricted fasting: Limiting eating to a certain window of time each day.

-In both short and long term studies, there was no additional weight loss when comparing these two types of fasting to standard calorie restriction.

-The study looked at the health effects of these diets on risk factors that included blood pressure, total cholesterol, HDL, LDL triglycerides, HbA1c and fasting glucose. The only significant difference was that the standard calorie restriction diet showed a more favorable effect on total cholesterol than time restricted fasting.

-More than half of the studies that reported side effects recorded adverse reactions to fasting. This included constipation, dizziness, diarrhea, headache, insomnia, low energy, strong feelings of hunger, difficulty concentrating, irritability, fatigue, bad breath, nausea, anxiety, hypoglycemia, cramps and palpitations.

Conclusions And Recommendations

This is a really well-done study by a top research university in a very well-regarded journal. For me the conclusions of this investigation are definitive. Looking at 99 randomized trials, it is clear that whole day fasting and time restricted eating are not better options than standard 3 meal a day calorie restriction.

These fasting methods do not result in additional weight loss, are not associated with improved health and seem to come with a whole host of side effects that don’t look like a lot of fun to me.

If you are trying to lose weight and improve your health, there is really no reason to starve yourself.

References

1) Semnani-Azad Z, et al. Intermittent fasting strategies and their effects of body weight and other cardiometab0lic risk factors. British Medical Journal 2025;389:e082007

 

Sunday, July 13, 2025

How much salt can I have?

Americans are currently consuming an average of 3,400 mg of sodium per day, which is too much. Excess sodium has been associated with hypertension and an increased risk of heart disease and stroke. It also can increase risk of kidney disease, stomach cancer and osteoporosis.

Based on the best current research evidence, the US Dietary Reference Intakes has calculated a Chronic Disease Risk Reduction Intake of 2,300 mg of sodium per day.

If you are otherwise healthy, this is a great level to shoot for. 


Recall For BowFlex SelectTech Dumbbells

I have previously reviewed and recommended BowFlex SelectTech Dumbells on this Blog/Newsletter. I have been using them myself for over 15 years. These are adjustable dumbbells that go from 2.5 to 52.5 lbs. with the turn of a dial.  

I just wanted to let you know that if you did pick these up, there has been a voluntary recall for this product. Appartently, in a few rare instances, the plates can dislodge and there is a risk of injury. The company is offering a pro-rated refund depending on when you bought them.

Here is a link from BowFlex for more info:

https://www.bowflex.com/dumbbell-recalls.html?lid=tx6wrdzvdw8l#different-remedies


Carbohydrate Consumption In Midlife And Healthy Aging

The Study

Research suggests that what we eat in midlife can have a significant impact on our health as we age. In this interesting study, 47,513 subjects from Harvard’s Nurses’ Health Study had their carbohydrate consumption measured from 1984-1986 and were followed until 2014.  

The goal was to see how different types of carbohydrate foods consumed in midlife influenced the odds of healthy aging. Healthy aging was considered to be an absence of major chronic disease, no cognitive or physical function impairments and good mental health.

The results were compelling:

-High quality carbohydrates were significantly and positively associated with healthy aging.

-Refined carbohydrates such as bread, white rice and sugar were significantly and negatively associated with healthy aging.

-Glycemic index was significantly and negatively associated with healthy aging.

-Fruits, vegetables, fiber and whole grains were significantly and positively associated with healthy aging.

JAMA Network Open. 2025;8(5):e2511056.

Take Home Message

Carbohydrates are a topic near and dear to my heart. I actually did my doctoral dissertation on carbohydrate metabolism. This is a thoughtful and important study. Many chronic diseases take decades to develop, so looking at how diet at midlife can impact healthy aging is a great idea.

The authors of the paper believed the tremendous benefit of healthy carbs was due to the impact of fiber on the gut microbiome and inflammation. The B vitamins and polyphenols found in healthy carbohydrate foods were also thought to be important.

Regardless of age, focus on healthy, high fiber sources of carbohydrate such as fruits, vegetables, legumes and whole grains like quinoa, oatmeal and brown rice. 

Strictly limit refined carbohydrates such as bread, pasta white rice and sugar.