An energy deficit of 3500 calories is needed to lose a pound of fat. Although this
simple formulation of weight gain and loss is generally valid, some research shows
that it matters where you get the extra calories. Although the human body can
convert surplus calories into fat from of each of the macronutrient categories (carbohydrates,
proteins, fats, and alcohol), the biochemical pathways for metabolizing
dietary fat, alcohol, and fructose, make it more likely that extra calories from these
sources will end up stored as fat.
There are hundreds of “weight loss” diets. Many of them work in the short term,
and when they work, it is by limiting the consumption of calories. For many of
these diets, elimination of certain types of foods, such as “carbs” or eating only a
limited array of foods, is the way they work to reduce the intake of calories. These
diets often give the appearance of very rapid weight loss. When the intake of calories
is lower than a person’s energy needs, the body first turns to glycogen stores for
energy. Stored glycogen accounts for 5% of the liver’s weight and makes up 1% of
muscle weight. So, the initial loss of weight is not from losing much fat; it is mostly
due to the mobilization and loss of glycogen to provide the body with energy that
is accompanied by loss of body water—a phenomenon that happens initially on all
calorie-restricted diets. After seven to 14 days, weight loss slows because the loss
of body fluids ends, and the body’s metabolism slows.
The effectiveness and health effects of high-fat (low carb) compared to low-fat diets
for long-term weight loss has long been debated. Many randomized controlled trials
(RCTs) and reviews have given inconclusive results. Among the popular “named”
diets are those that are low carbohydrate (e.g., Atkins, South Beach, Zone), those
that are moderate in the proportion of macronutrients (e.g., Biggest Loser, Jenny
Craig, Nutrisystem, Volumetrics, and WeightWatchers) and those that are low-fat
(e.g., Ornish, Rosemary Conley).
A meta-analysis of 48 randomized trials of popular
diets showed that both low-carbohydrate and low-fat diets were associated with
an estimated 8-kg (17.6 lb.) weight loss at 6-month follow-up compared with no
diet. Their research suggests the choice of almost any diet that cuts calories and that
you can adhere to will cause you to lose weight.
This blog presents opinions and ideas and is intended to provide helpful general information. I am not engaged in rendering advice or services to the individual reader. The ideas, procedures and suggestions in that are presented are not in any way a substitute for the advice and care of the reader’s own physician or other medical professional based on the reader’s own individual conditions, symptoms or concerns. If the reader needs personal medical, health, dietary, exercise or other assistance or advice the reader should consult a physician and/or other qualified health professionals. The author specifically disclaims all responsibility for any injury, damage or loss that the reader may incur as a direct or indirect consequence of following any directions or suggestions given in this blog or participating in any programs described in this blog or in the book, The Building Blocks of Health––How to Optimize Your Health with a Lifestyle Checklist (available in print or downloaded at Amazon, Apple, Barnes and Noble and elsewhere). Copyright 2021 by J. Joseph Speidel.