"Even with carbohydrate consumption..." LOL! It amazes me that the idea that eating carbohydrates impedes fat loss has such a grip not only on laypeople, but also on scientists who I would expect to be better informed.
From Science Daily:
It really isn't a surprise to me. In Powered By Plants I already discussed the significant body of research that indicates that eating animal products promotes wait gain, overweight, and obesity. The probable mechanisms include:
"Weight loss was not the only positive outcome for participants in the
strictly vegan group. They also showed the greatest amount of decrease
in their fat and saturated fat levels at the two and six month checks,
had lower BMIs, and improved macro nutrients more than other diets.
Eschewing all animal products appears to be key for these positive
results. 'I personally was surprised that the pesco-vegetarian group
didn't fare better with weight loss. In the end, their loss was no
different than the semi-vegetarian or omnivorous groups,' McGrievy said."
- Animal products tend to have a higher caloric density (kcal/g) and are less bulky than most plant products, so that when the diet consists of whole plant foods it is physically more difficult to over-consume calories.
- Animal products contain no dietary fiber and are consequently more digestible than most plant products, so when the diet is rich in whole plant foods with no animal products there is greater fiber-related satiety and a lower net caloric absorption .
- Animal products tend to have more total fat than most plant products, and dietary fat is less satiating per kcalorie consumed and becomes body fat much more easily than either carbohydrate or protein from plants. Fish oil supplementation has even been found to increase appetite , which may help explain why the pesco-vegetarian group in the above study achieved no better weight loss results than consumers of land animal products.
- Animal products tend to contain more saturated fat than plant products, and saturated fats tend to reduce insulin sensitivity , reducing glucose delivery to cells which may stimulate appetite, particularly for high energy density sweets and desserts or liquid sugar solutions.
- Animal products contain less glucose than plant products, and glucose is the preferred food of the central nervous system. When animal products displace plant products, the reduced total intake of and gut exposure to glucose and fructose may result in less satiation  than when consuming a plant based diet. This may also be a cause for sweets cravings, resulting in over-consumption of desserts which typically have a high energy density due to their contents of fat and refined sugars.
- Due to its higher content of essential amino acids, animal protein stimulates more fat-storing insulin release and less fat-mobilizing glucagon release than plant protein. This is especially true when animal protein is combined with carbohydrates. Animal protein may also decrease insulin sensitivity. Therefore, replacing animal protein with plant protein favors fat oxidation over fat storage. [5, 6, 7]
- The more complex the food, the more energy expended to digest and assimilate its contents. Whole plant foods have very complex compositions. A diet of whole plant foods involves a significantly greater post-meal diet-induced thermogenesis (expenditure of energy as heat) due to the presence of fiber and phytochemicals.